The U.S. wants to stop Iran and its allies from spreading conflict in the Middle East following the killing of Hezbollah’s leader in Lebanon, the Pentagon said on Sunday.

“Secretary Austin stressed that the United States is determined to prevent Iran and Iranian-backed partners and proxies from exploiting the situation or expanding the conflict,” Pentagon Press Secretary Maj. Gen. Pat Ryder said in a statement.

“Secretary Austin made clear that should Iran, its partners, or its proxies use this moment to target American personnel or interests in the region, the United States will take every necessary measure to defend our people.”

The statement comes amid concerns that conflict could spread further across the Middle East and spark a wider war after Hassan Nasrallah was killed in an Israeli airstrike in Lebanon last week. Israel’s military has indicated that it is preparing to invade southern Lebanon and said Sunday it had launched additional raids on targets in Lebanon.

The Department of Defense also said it “continues to maintain a significant amount of capability in the region and to dynamically adjust our force posture based on the evolving security situation.”

“The Secretary has also increased the readiness of additional U.S. forces to deploy, elevating our preparedness to respond to various contingencies,” Ryder said in the statement. “And DoD maintains robust and integrated air-defense capabilities across the Middle East, ensuring the protection of U.S. forces operating in the region.”

White House officials said Friday afternoon that President Biden had directed the Pentagon to “assess and adjust as necessary U.S. force posture in the region to enhance deterrence, ensure force protection, and support the full range of U.S. objectives.”

Iran provides weapons and other support to Hezbollah, Hamas in Gaza and the Houthis in Yemen, while the U.S. is a strong ally of Israel and has provided the country with billions of dollars’ worth of military aid each year.