President Trump announced a three-week extension of a cease-fire between Israel and Lebanon that had been set to expire in a few days, after hosting a meeting between Israeli and Lebanese diplomats at the White House on Thursday.

Hezbollah, the Iranian-backed militant group that has been attacking Israel from southern Lebanon, did not have representatives at the meeting and did not immediately comment on the announcement. The prime minister of Israel and the president of Lebanon also did not comment.

A successful peace agreement would hinge upon Hezbollah halting attacks, which Lebanon’s government has little power to enforce because it does not control the militia. Lebanon’s military has mostly stayed out of the fighting and is not at war with Israel.

The cease-fire, which was scheduled to end on April 26, would last until May 17 if it takes effect as Mr. Trump described it. Before the cease-fire was brokered last week, nearly 2,300 people were killed in Lebanon and 13 in Israel. Since then, the number of Israeli airstrikes and Hezbollah attacks have been dramatically reduced, though the two sides have continued exchanging fire.

The Lebanese Ambassador to the United States, Nada Hamadeh, credited Mr. Trump for extending the cease-fire, saying that “with your help and support, we can make Lebanon great again.” Mr. Trump replied, “I like that phrase, it’s a good phrase.”

Asked about the potential of a lasting peace agreement between Israel and Lebanon, Mr. Trump said that “I think there’s a great chance. They are friends about the same things and they are enemies on the same things.”

But Lebanon and Israel have periodically been at war since Israel’s founding in 1948. Israel has invaded Lebanon for the fifth time since 1978, incursions that have destabilized the country and the delicate balance of power between Muslim, Christian and Druze communities.

In the hours before the president’s announcement on social media, Israel and Hezbollah were trading attacks in southern Lebanon, testing the existing cease-fire.

Mr. Trump said the meeting at the White House had been attended by high-ranking U.S. officials, including Vice President JD Vance, Secretary of State Marco Rubio and the U.S. ambassadors to Israel and Lebanon.

Earlier on Thursday, an Israeli strike near the southern Lebanese city of Nabatieh killed three people, according to Lebanon’s health ministry. Hezbollah claimed three separate attacks on Israeli troops who are occupying southern Lebanon, though none were wounded or killed.

Hezbollah set off the latest round of fighting last month by attacking Israel soon after the start of the U.S.-Israeli bombing campaign in Iran. Israel responded to Hezbollah’s attacks by launching airstrikes across Lebanon and widening a ground invasion of the country’s south.

The Senate early Thursday morning adopted a Republican budget blueprint that would pave the way for a $70 billion increase for immigration enforcement and the eventual reopening of the Department of Homeland Security.

Republicans pushed through the plan on a nearly party-line vote of 50 to 48. It came after an overnight marathon of rapid-fire votes, known as a vote-a-rama, in which the G.O.P. beat back a series of Democratic proposals aimed at addressing the high cost of health care, housing, food and energy. The debate put the two parties’ dueling messages on vivid display six months before the midterm elections.

Republicans, who are using the budget plan to lay the groundwork to eventually push through a filibuster-proof bill providing a multiyear funding stream for President Trump’s immigration crackdown, used the all-night session to highlight their hard-line stance on border security, seeking to portray Democrats as unwilling to safeguard the country.

Democrats tried and failed to add a series of changes aimed at addressing cost-of-living issues, seizing the opportunity to hammer Republicans as out of touch with and unwilling to act on the concerns of everyday Americans.

Here’s what to know about the budget plan and the nocturnal ritual senators engaged in before adopting it.

Republicans are seeking a way around a filibuster on D.H.S. funding.

The budget blueprint is a crucial piece of Republicans’ plan to fund the Department of Homeland Security and end a shutdown that has lasted for more than two months. After Democrats refused to fund immigration enforcement without new restrictions on agents’ tactics and conduct, the G.O.P. struck a deal with them to pass a spending bill that would fund everything but ICE and the Border Patrol. Republicans said they would fund those agencies through a special budget bill that Democrats could not block.

“We can fix this with Republican votes, and we will,” said Senator Lindsey Graham, Republican of South Carolina and the Budget Committee chairman. “Every Democrat has opposed money for the Border Patrol and ICE at a time of great peril.”

In resorting to a new budget blueprint, Republicans laid the groundwork to deny Democrats a chance to stop the immigration enforcement funding. But they also submitted themselves to a vote-a-rama, in which any senator can propose unlimited changes to such a measure before it is adopted.

The budget measure now goes to the House, which must adopt it before lawmakers in both chambers can draft the legislation funding immigration enforcement. That bill will provide yet another opportunity for a vote-a-rama even closer to the November election.

Democrats used the moment to hammer Republicans on affordability.

Democrats took to the floor to criticize Republicans for supercharging funding for federal immigration enforcement rather than moving legislation that would address Americans’ concerns over affordability.

“This is what Republicans are fighting for,” said Senator Chuck Schumer, Democrat of New York and the Democratic leader. “To maintain two unchecked rogue agencies that are dreaded in all corners of this country instead of reducing your health care costs, your housing costs, your grocery costs, your gas costs.”

Democrats offered a host of amendments along those lines, all of which were defeated by Republicans — and that was the point. The proposals were meant to put the G.O.P. in a tough political spot, showcasing their opposition to helping Americans afford high living costs. Fewer than a handful of G.O.P. senators crossed party lines to support them.

Republicans blocked Democrats’ proposals to address high living costs.

The G.O.P. thwarted an effort by Mr. Schumer to require that the budget measure lower out-of-pocket health care costs for Americans. Two Republicans who are up for re-election this year, Senators Susan Collins of Maine and Dan Sullivan of Alaska, voted with Democrats, but the proposal was still defeated.

Republicans also squelched a move by Senator Ben Ray Lujan, Democrat of New Mexico, to create a fund that would lower grocery costs and reverse cuts to food aid programs that Republicans enacted last year. Ms. Collins and Mr. Sullivan again joined Democrats.

Also defeated by the G.O.P.: a proposal by Senator John Hickenlooper, Democrat of Colorado, to address rising consumer prices brought on by Mr. Trump’s tariffs and the war in Iran; one by Senator Edward J. Markey, Democrat of Massachusetts, to require the budget measure to address rising electricity prices, and another by Mr. Markey to create a fund to bring down housing costs.

Senator Jon Ossoff, a Democrat who is up for re-election in Georgia, also sought to add language requiring the budget plan to address health insurance companies denying or delaying access to care, but that, too was blocked by Republicans.

Republicans sought to amplify their hard-line messages on immigration, voter I.D. and transgender care.

While Republicans had fewer proposals for changes to their own budget plan, they also sought to offer measures that would underscore their aggressive stance on immigration enforcement and dare Democrats to vote against them.

Mr. Graham offered an amendment to allocate funds toward a deficit-neutral reserve fund relating to the apprehension and deportation of adult immigrants convicted of rape, murder, or sexual abuse of a minor after illegally entering the United States. It passed unanimously.

Senator Josh Hawley, Republican of Missouri, sought to bar Medicaid payments to Planned Parenthood, which provides abortion and other services, and criticized the organization for providing transgender care to minors. Senator John Kennedy, Republican of Louisiana, also attempted to tack on the G.O.P. voter identification bill, known as the SAVE America Act. Both proposals were blocked when Democrats, joined by a few Republicans, voted to strike them as unrelated to the budget plan.

The Republicans who crossed party lines to oppose their own party’s proposals for new voting requirements were Ms. Collins along with Senators Mitch McConnell of Kentucky, Lisa Murkowski of Alaska and Thom Tillis of North Carolina.

Ms. Collins and Ms. Murkowski also opposed the effort to block payments to Planned Parenthood.