The United States is in the midst of an intense diplomatic push to prevent full-on war between Israel and Hezbollah forces in Lebanon, as the risks rise that either side could initiate a broader regional fight.

In recent days, U.S. officials have pressed their Israeli counterparts and passed messages to Hezbollah’s leaders with the goal of averting a wider regional conflict that they fear could draw in both Iran and the United States.

Israel’s defense minister, Yoav Gallant, met with several Biden administration officials in Washington this week, in large measure to discuss the escalating tensions along Israel’s northern border with Lebanon. That visit followed one last week by Israel’s national security adviser, Tzachi Hanegbi, and its minister of strategic affairs, Ron Dermer.

Also last week, a senior White House official, Amos Hochstein, who has assumed an informal diplomatic role mediating between the two sides, visited Israel and Lebanon. Mr. Hochstein warned Hezbollah, which is supported by Iran, that the United States would not be able to restrain Israel should it commit to an all-out war with the militia group.

Archrivals for decades, Israel and Hezbollah have frequently exchanged fire along Israel’s northern border. After the Hamas-led attacks on Oct. 7 triggered a blistering Israeli assault in Gaza, Hezbollah began firing at Israel, mainly against Israeli military targets in northern Israel to show solidarity with Hamas, which is also backed by Iran.

The fighting has intensified in recent weeks, and Israel’s reduced combat operations in Gaza, where it has greatly weakened Hamas, have freed up more of its forces for a possible offensive in the north.