Tehran has made a ceasefire in Lebanon a condition for any peace deal with Washington, and has suggested it could intervene directly in support of its proxy Hezbollah if Israel keeps up its attacks there.
Lebanese President Joseph Aoun said on Thursday the ceasefire would come into force within 24 hours of all concerned parties approving it, appearing to refer to Hezbollah, which has not commented on the agreement.
But casting doubt on the robustness of the truce, Israeli Defence Minister Israel Katz said the military would continue to strike in Lebanon for the time being and would not withdraw from the south.
The deal comes after a flare-up in violence across the region.
Israeli strikes killed at least six people in southern Lebanon and US and Iranian forces traded attacks in the Gulf on Wednesday in one of the most intense bouts of fighting since a separate ceasefire halted large-scale US-Israeli bombing of Iran in early April.
Iranian forces struck Kuwait, damaging its airport and injuring dozens, while the US military carried out strikes near the Strait of Hormuz.
The strait, through which a fifth of the global oil and liquefied natural gas supplies usually flow, remains largely closed more than three months after the US and Israel launched their strikes on Iran.
US President Donald Trump, who is under pressure to bring down fuel prices, suggested there could be progress in negotiations with Iran within days.
"If it happens, it could happen over the weekend," Trump told reporters at the White House on Wednesday.
Trump said parties were working to separate the issue of reopening the strait from the conflict in Lebanon.
Wednesday's strikes on Kuwait damaged airport facilities and diplomatic missions, killing one person and injuring dozens more, authorities said.
Iran's Revolutionary Guards said they did not fire at Kuwait's airport and blamed the destruction on US interceptor missiles that failed to hit their targets.
The US military said that was not accurate, and that Iranian drones targeted the airport deliberately.
Iranian media reported the Revolutionary Guards also attacked the headquarters of the US Fifth Fleet in Bahrain and a US air base.
US Central Command denied its bases had been hit and said Iranian missiles failed to strike their targets in the region.
The US said it had carried out a new round of "defensive strikes" in southern Iran, targeting missile launch sites and Iranian boats seeking to lay mines.
Iran and the US in late May signalled progress towards an initial agreement to halt the war and reopen the strait, but they have yet to approve the deal, which would leave more complex negotiations for later.
Iran's supreme leader said in a message on Thursday that Iran's enemies had already been defeated on the battlefield and were now seeking to sow internal divisions.
"In order to confront these plans everyone must be patient, clear-minded, maintain unity, harmony, mutual trust, and not be in agreement with the enemy," Ayatollah Mojtaba Khamenei said in a message read on his behalf during ceremonies marking the anniversary of the death of the Islamic Republic's founder, Ruhollah Khomeini.
Khamenei has not been seen in public since he succeeded his father, who was killed in an air strike at the start of the war.
As well as Tehran conditioning a deal on an end to fighting in Lebanon, it also wants access to billions of dollars in oil revenue, sanctions relief, a lifting of a US port blockade, and continued leverage over the strait.
Trump has said his top priority is to stop Iran from acquiring nuclear weapons.
Iran says its atomic program is for peaceful purposes.
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