The United States has assessed that Iran manufactured the drone that slammed into a US base in Jordan over the weekend, killing three US soldiers and wounding more than 40, four US officials told Reuters.
Washington has blamed the attack - the first to kill US troops in the Middle East since the start of the Israel-Hamas war in October - on Iran-backed militants. But it has also said it ultimately holds Iran responsible, given its support for the organizations.
The officials, who spoke on condition of anonymity, did not disclose details of the drone's model.
While the initial indications were that the drone was likely Iranian, a formal assessment was made only recently after recovering fragments of the drone.
Kataib Hezbollah, a pro-Iranian militia based in Iraq, said on Tuesday it was suspending military actions against the United States to avoid embarrassing the Baghdad government.
President Joe Biden's administration said it was not seeking a war with Iran, even as Republican pressure on him to respond forcefully has been rising.
'No US threat to Iran will go unanswered'
Iranian officials have said Tehran will respond to any threat from the United States. Iran's envoy to the US said Tehran would respond decisively to any attack on its territory, its interests, or Iranian nationals outside its borders.
US troops have been attacked more than 160 times in Iraq, Syria, and Jordan since the events of Oct. 7 that triggered the war in Gaza, and warships have seen attacks in the Red Sea as well. Houthi fighters in Yemen have fired drones and missiles at them on the Red Sea in solidarity with the Palestinians.
The United States has already retaliated in Iraq, Syria, and Yemen in response to previous attacks by Iran-backed groups.
Experts have cautioned that any strikes against Iranian forces inside Iran could force Tehran to respond, escalating the situation in a way that could drag the United States into a major Middle East war.