Iran has made a ceasefire between Israel and Hezbollah a condition for any peace deal with Washington to resolve the regional war, now in its fourth month, and restart shipping through the Strait of Hormuz.
The latest round of fighting between Hezbollah and Israel erupted at the start of March, two days after the US and Israel launched strikes against Iran.
Hezbollah said its actions were in support of Tehran.
"This war will end only when it ends in Lebanon as well," Iranian Foreign Minister Abbas Araqchi told Lebanese TV station Al Mayadeen late on Thursday.
"The end of the war on Lebanon must be accompanied by the withdrawal of Israeli forces from the territories they have occupied," he said.
The comments came after Hezbollah leader Naim Qassem rejected a US-brokered pact between Israel and the Lebanese government to halt the fighting in Lebanon.
The deal did not provide for an Israeli withdrawal and Hezbollah had not been party to the negotiations.
Israel has kept up strikes in southern Lebanon, and has said its forces would not withdraw or halt operations in the country.
Mohsen Rezaei, an adviser to Iran's supreme leader, said Hezbollah had "made great sacrifices in the recent war and it is our ally".
"Therefore, we support Hezbollah and remain firmly committed to our obligations toward it."
In comments reported by the semi-official Mehr news agency, he cautioned Israel against following through on threats to resume strikes against the Lebanese capital, Beirut.
"Today we again warn this sinister regime to leave Lebanon. They should know that Lebanon will be an inseparable part of any agreement and any ceasefire."
In Washington, President Donald Trump told reporters he believed progress was being made in Lebanon and the country deserved to have peace, adding, "It's been going on for a long time, you know."
Along with Lebanon, residents of Gaza, northern Israel and Kuwait have been under fire despite US-arranged ceasefires that Trump said involved "shooting in a more moderate manner", rather than a total halt to fighting.
On Wednesday, Iranian and US forces traded attacks in the Gulf in one of the most intense bouts of fighting since early April, when a ceasefire halted large-scale hostilities.
After the US and Israel launched the war against Iran on February 28, Iran fired missiles and drones against Gulf states hosting US bases and largely stopped shipping through the Strait of Hormuz.
Trade remains at a fraction of its former levels through the waterway, which previously carried about a fifth of global oil and liquefied natural gas supplies.
The conflict has driven up oil prices and disrupted supply chains for other products.
The US and Iran have been engaged in largely indirect negotiations to secure an interim deal to halt the war that would leave issues including Iran's nuclear program to further negotiations.
As part of any agreement, Tehran wants access to billions of dollars in oil revenue, waivers on sanctions on crude exports, a lifting of a US blockade on its ports and leverage over the strait.
Trump, who has said his top priority is to stop Iran from acquiring nuclear weapons, told reporters Washington did not need a deal with Iran to extract enriched uranium from the country.
"I don't think they could stop us if we wanted, but there's no reason to," he said in the Oval Office.
"It's entombed."
with DPA
