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.