Israel and Lebanon sent diplomatic envoys to a meeting of a U.S.-led cease-fire monitoring committee for the first time on Wednesday, broadening the talks as fears grew that Israel might renew its offensive against Hezbollah.

Until now, only military officials from both countries have met with representatives from the United States, France and the U.N. peacekeeping force in Lebanon. But an escalation in the severity of Israeli attacks on the Lebanese militant group Hezbollah has increasingly tested the year-old truce.

Israeli and U.S. officials have been warning that Israel could launch a new offensive against Iran-backed Hezbollah if Lebanon's government does not hasten the disarmament of the group, as required under the cease-fire.

Analysts saw the shift as a significant step toward expanding talks between Israel and Lebanon during a deepening quagmire. Hezbollah has resisted nationwide disarmament unless Israel makes concessions, including an end to its attacks on Lebanon and a withdrawal from several small areas it still controls on Lebanese territory.

But Israel has refused to meet those demands before Hezbollah disarms.

"There is a strong push within the government to disarm," said Mohanad Hage Ali, a senior fellow at the Carnegie Middle East Center in Beirut, referring to Lebanon. "But, at the same time, disarming an organization with popular roots within its own community as Israel continues to occupy and bombard Lebanon is a no-brainer cause of tensions internally," he added.

"The Lebanese government is keen to avoid that and reach a solution," he said.

The U.S.-led monitoring committee was established to oversee a truce that ended the deadliest conflict between Israel and Hezbollah in decades. For months now, the Trump administration has pushed to widen talks between Israel and Lebanon, which began after the cease-fire was reached a year ago.

Lebanon's president, Joseph Aoun, has signaled that his country would be open to negotiations with Israel to solidify the shaky truce. But such talks remain contentious within Lebanon, which has officially been in a state of war with Israel since it was founded in 1948.

The office of Prime Minister Benjamin Netanyahu of Israel said on Wednesday that Israel would send a representative from his National Security Council to the cease-fire committee.

"This is a first attempt at establishing a relationship and economic cooperation between Israel and Lebanon," the statement from Mr. Netanyahu's office said.

Mr. Aoun's spokesman said Lebanon had appointed Simon Karam, a former ambassador to Washington, to lead its delegation.

The cease-fire monitoring committee met on Wednesday on Lebanese territory near the border with Israel.

A Trump envoy to the Middle East, Morgan Ortagus, attended the meeting a day after she visited Israel to meet with officials there.

The U.S. Embassy in Lebanon said after the meeting that the addition of the diplomatic officials reflected a commitment to achieving security, stability and a durable peace.

Johnatan Reiss contributed reporting.

Euan Ward is a Times reporter covering Lebanon and Syria. He is based in Beirut.