US Treasury Secretary Scott Bessent has directed a team to assess costs for damages already inflicted on Gulf allies by Iran, the source said, adding the United States will consider using Iranian assets for repairs of any future destruction as well.
Saturday's disclosure came a day after Mohsen Rezaei, an adviser to Iran's supreme leader, told CNN that a peace deal to end the three-month war hinged on the release of $US24 billion ($A34 billion) in Iranian assets frozen by the US.
The source on did not specify what kind of assets the Treasury was examining. The language used to describe the new measures did not appear limited to frozen assets.
The threatened redirection of Iranian assets could create a new irritant to a fragile ceasefire between the US and Iran, which was tested again this weekend with strikes by both nations.
Peace negotiations appear to have stalled, although a minister from mediator Pakistan travelled to Tehran on Saturday with a letter for Iran's Supreme Leader Ayatollah Mojtaba Khamenei, Iran's semi-official ISNA news agency reported.
US forces struck Iranian coastal radar sites in Goruk and Qeshm Island, both in the Strait of Hormuz, on Saturday after shooting down drones launched by Iran that US Central Command says posed a threat to maritime traffic.
A further two Iranian attack drones that were threatening shipping in the strait were also shot down, the US military said late on Saturday.
A deal has remained elusive while the two sides have periodically skirmished.
Tehran wants access to billions of dollars in oil revenue, waivers on sanctions on crude exports, the lifting of a US blockade on its ports and leverage over the Strait of Hormuz. Iran has effectively blocked the waterway, where about one-fifth of global oil traffic transited before the war.
Iranian state media reported that Pakistani Interior Minister Mohsin Naqvi arrived in Tehran on Saturday for talks with Iranian officials, including Foreign Minister Abbas Araqchi. Naqvi said he was carrying a "special letter" from his country's army chief and prime minister to Khamenei, ISNA reported.
Trump is facing mounting domestic political pressure due to rising gas prices to bring the unpopular war to an end. He told NBC that while most of Iran's drone and missile manufacturing facilities had been destroyed, the Iranians still had access to about one-fifth of their missiles.
"They have some missiles, they have some drones. I would say percentage wise, maybe 21 to 22 per cent of their missiles. It's a lot of missiles, but it's not what it was when we first attacked," Trump told NBC News' Meet the Press program, according to excerpts released by the network on Friday.
In a parallel conflict in Lebanon, two Lebanese army officers and a soldier were killed in an Israeli strike on a military vehicle in south Lebanon, the Lebanese army said. The Israeli military said it was investigating the incident. Iran has made a ceasefire in Lebanon between Israel and Iran-aligned Hezbollah a condition for any peace deal with Washington.
Hezbollah leader Naim Qassem this week 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 said its forces would not withdraw or halt operations in the country amid increasing friction with the US.
with DPA