Seven US personnel were wounded in a rocket attack by Iran-backed militias on a base in Iraq, underscoring the threat to American forces amid intensified diplomatic efforts to ease tensions between Iran and Israel.

US defence secretary Lloyd Austin said the attack on Ain al-Assad, the main base hosting American forces in Iraq, “marked a dangerous escalation and demonstrated Iran’s destabilising role in the region”, according to a Pentagon readout of a call with his Israeli counterpart.

The assault on Monday was the first time in months that American troops in Iraq have been wounded, and followed a US strike against Iran-backed Iraqi militias last week.

Two rockets hit the airbase at about 9pm local time on Monday, wounding five US soldiers and two American contractors, a US defence official said. Two were evacuated from Iraq for further treatment and all are in a stable condition, the official said.

The Ain al-Assad attack took place as Washington and its Arab allies sought to reduce soaring regional tensions following the back-to-back assassinations of senior leaders of the Lebanese militant movement Hizbollah and Hamas last week.

Both Iran and Hizbollah have vowed to retaliate against Israel after Fuad Shukr, a Hizbollah commander, was killed by an Israeli strike on Beirut, and Ismail Haniyeh, Hamas’s political leader, was assassinated in Tehran.

US secretary of state Antony Blinken said Washington was “engaged in intense diplomacy pretty much around the clock with a very simple message: all parties must refrain from escalation, all parties must take steps to ease tensions”.

An Iranian official told the Financial Times that the US had sent messages to Tehran through Jordan, Oman and Qatar urging the republic not to escalate the situation, saying that would not be in its interests. But Iran’s response has been that “we have made our decision”, the official said. 

Hizbollah’s leader on Tuesday said the group would respond to the killing of its most senior military commander, regardless of international diplomacy and “no matter the consequences”.

“Our response will come. Alone, or with the Axis [of Resistance],” Hassan Nasrallah said, referring to the network of Iran-backed groups in the region, in a speech marking a week since Israel’s assassination of Shuk.

“These are all possibilities,” he said, adding that the uncertainty over the retaliation was psychological warfare and was part of Israel’s punishment.

Blinken said to “break this cycle”, there needed to be a ceasefire to end the 10-month war between Israel and Hamas in Gaza, urging the sides to accept a deal.

The US, along with Qatar and Egypt, have for months been seeking to broker a deal to secure the release of hostages in Gaza and halt the war in the besieged strip, which is considered vital to ending the regional hostilities that erupted after Hamas’s October 7 attack.

But they have struggled to get the parties to agree a deal, and mediators have warned that the killing of Haniyeh, Hamas’s main negotiator, has further set back the talks.

The fear is that a robust retaliation to the assassinations by Iran and Hizbollah will trigger an Israeli counter-response and push the region closer to a full-blown war.

Hizbollah and Israel continued to trade fire on Tuesday, with Lebanese authorities saying at least six people were killed in Israeli strikes, one of which targeted the town of Mayfadoun, some 30km inside Lebanon. At least four of those people were Hizbollah fighters. 

Israeli health authorities said seven people were wounded, including one critically, after a Hizbollah barrage, although the Israel Defense Forces later clarified that one of its own air defence interceptor missiles “missed the target and hit the ground, injuring several civilians”. The IDF said the incident was under review. 

There are also concerns that Iran could mobilise the militant groups in the so-called Axis of Resistance, which includes Houthi rebels in Yemen and militias in Iraq and Syria, as well as Hizbollah and Hamas.

The US has moved additional military assets, including warships and fighter jets, to the region to help defend Israel and in a show of deterrence. But there is a risk that its forces are sucked into combat.

There are about 2,500 American troops in Iraq and about 900 in Syria, where they have been part of an international coalition fighting Isis, the jihadi group.

Iran-backed militias have launched multiple rocket and drone strikes against US forces since the October 7 attack and Israel’s retaliatory offensive in Gaza triggered a wave of regional hostilities.

Those attacks had diminished in intensity after the US launched air strikes against Iran-affiliated targets in Syria following an attack on a US base on the border between Jordan and Syria that killed three American soldiers in January.

Ain al-Assad base has been targeted at least twice in the past month.

The Houthis have also launched attacks against US navy vessels that have been patrolling the Red Sea in an effort to prevent the Yemeni rebels’ assaults on merchant shipping in the key maritime trade route.

Iranian leaders stepped up their threats against Israel on Monday as the region braced for the Islamic republic’s response, with President Masoud Pezeshkian warning that Tehran would “definitely” respond to Haniyeh’s killing.

He said Iran was not seeking to “expand the scope of war” in the region but Israel “will definitely receive a response for its crimes and insolence”.

Israel has neither denied nor confirmed responsibility for Haniyeh’s killing.

Additional reporting by Raya Jalabi in Beirut and Neri Zilber in Tel Aviv

TAIPEI, Taiwan (AP) — Chinese-American physicist Tsung-Dao Lee, who in 1957 became the second-youngest scientist to receive a Nobel Prize, died Sunday at his home in San Francisco at age 97, according to a Chinese university and a research center.

Lee, whose work advanced the understanding of particle physics, was one of the great masters in the field, according to a joint obituary released Monday by the Tsung-Dao Lee Institute at Shanghai Jiao Tong University and the Beijing-based China Center for Advanced Science and Technology.

Lee, a naturalized U.S. citizen since 1962, was also a professor emeritus at Columbia University in New York.

Robert Oppenheimer, known as the father of the atomic bomb, once praised Lee as one of the most brilliant theoretical physicists of the time, whose work showed “remarkable freshness, versatility and style.”

Lee was born in Shanghai on Nov. 24, 1926, the third of six children to a merchant father, Tsing-Kong Lee, and a mother, Ming-Chang Chang, who was a devout Catholic, according to local newspaper Wenhui Daily.

He went to high school in Shanghai and attended National Chekiang University in Guizhou province and National Southwest Associated University in Kunming in Yunnan province.

After his sophomore year, he received a scholarship from the Chinese government to attend graduate school in the United States.

Between 1946 and 1950, he studied at the University of Chicago under Enrico Fermi, a Nobel laureate in physics.

In the early 1950s, Lee worked at the Yerkes Observatory in Wisconsin, at the University of California at Berkeley and at the Institute for Advanced Study in Princeton, N.J.

His research in elementary particles, statistical mechanics, astrophysics and field theory, among others, was standing out.

In 1953, he joined Columbia University as an assistant professor. Three years later, at age 29, he became the youngest-ever full professor there. He developed a model for studying various quantum phenomena known as the “Lee model.”

In 1957, Lee was awarded the Nobel Prize in physics together with Chen-Ning Yang for work exploring the symmetry of subatomic particles as they interact with the force that holds atoms together. At 31, Lee was the second-youngest scientist to receive the distinction.

He won many other accolades including the Albert Einstein Award in Science, the Galileo Galilei Medal and the G. Bude Medal, as well as honorary doctorates and titles from organizations around the world.

As China became more open to international exchanges in the 1970s, Lee returned to his home country on repeated visits to give lectures and encourage the development of sciences, according to state media.

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Student protesters in Bangladesh have called for Nobel Peace Prize winner Muhammad Yunus to be named chief adviser of a new interim government after Prime Minister Sheikh Hasina fled the country in the face of a popular uprising.

Sheikh Hasina, who governed the country for two decades, was ousted with startling speed on Monday after weeks of violent protests over an unpopular job quota scheme swelled into a youth-led movement that demanded she step down.

The Dhaka Tribune reported that at least 135 people died on Monday as thousands of protesters demanding Sheikh Hasina quit marched on her residence and took control of the streets of Dhaka, the capital.

Army chief Waker-Uz-Zaman said the military would hold talks with President Mohammed Shahabuddin and political party representatives on forming a new government. Shahabuddin also ordered the release of jailed ex-prime minister Khaleda Zia and student protesters.

“We have decided that an interim government will be formed in which internationally renowned Nobel laureate Dr Muhammad Yunus, who has wide acceptability, will be the chief adviser,” Nahid Islam, an organiser of the Anti-Discrimination Student Movement, said in a video statement.

“We have spoken to Dr Muhammad Yunus and, at the call of the students and to protect Bangladesh, Dr Muhammad Yunus has decided to take on the responsibility.”

An official from Yunus’s office confirmed that he had accepted the students’ request. 

Yunus, 84, who won the Nobel Peace Prize in 2006, is the founder of pioneering microlender Grameen Bank and one of the south Asian country’s most prominent figures. He has faced multiple court cases as part of what his supporters described as a politically motivated vendetta by Sheikh Hasina, who saw him as a potential rival.

On Tuesday, India’s government confirmed that Sheikh Hasina had arrived in Delhi on Monday evening.

“At very short notice, she requested approval to come for the moment to India,” S Jaishankar, India’s external affairs minister, told parliament. “We simultaneously received a request for flight clearance from the Bangladesh authorities. She arrived yesterday evening in Delhi.”

According to some reports, Sheikh Hasina plans to seek refuge in the UK, where her niece, Tulip Siddiq, is an MP with the ruling Labour party and serves as economic secretary to the Treasury.

However, British officials played down the prospect of Sheikh Hasina being welcomed in the UK, noting there was no provision in the country’s immigration rules allowing somebody — even a fleeing prime minister — to travel to the UK to seek asylum or temporary refuge.

Britain’s policy is to urge anyone seeking international protection to claim asylum in the first safe country they reach as the fastest route to safety, said the officials, who requested anonymity.

Sheikh Hasina’s ousting has thrown Bangladesh’s turbulent politics and struggling economy into further disarray. The prime minister, who claimed a fifth term in power this year after a disputed election, had ruled with an increasingly authoritarian hand.

On Monday, as news of Sheikh Hasina’s flight spread, protesters attacked and looted her former residence and other buildings, news footage showed, in scenes that recalled the 2022 uprising in Sri Lanka that overthrew Gotabaya Rajapaksa as president.

People also attacked statues of Sheikh Hasina’s father, independence hero Sheikh Mujibur Rahman, who was the subject of a personality cult promoted by the prime minister and her Awami League party.

The protest movement was sparked by a quota system reserving coveted civil service jobs for specific groups, including descendants of veterans who served in the country’s 1971 civil war in which it split from Pakistan. About 300 people were killed in a crackdown on the demonstrations in the weeks before Sheikh Hasina’s resignation.

“There is a lot of anger and frustration and very high expectations that all of the bad things that have been done will be addressed quickly,” said Badiul Alam Majumdar, activist and secretary of Shujan: Citizens for Good Governance, a non-governmental organisation.

“Violence and taking revenge is not acceptable and that needs to stop,” he added. “We have a new beginning.”

Additional reporting by Jyotsna Singh in New Delhi