An enemy drone that killed three American troops and wounded dozens of others in Jordan may have been confused with an American drone returning to the US installation, two US officials said on Monday.

The officials, who were not authorised to comment and insisted on anonymity, said preliminary accounts suggest the enemy drone that struck the installation known as Tower 22 may have been mistaken for an American drone that was in the air at the same time.

The officials said that as the enemy drone was flying in at a low altitude, a US drone was returning to the base. As a result, there was no effort to shoot down the enemy drone.

The preliminary conclusion was first reported by The Wall Street Journal.

The explanation for how the enemy drone evaded US air defences on the installation came as the White House said on Monday it’s not looking for war with Iran even as President Joe Biden vows retaliatory action. The Democratic administration believes Tehran was behind the strike.

Biden met members of his national security team in the White House Situation Room to discuss the latest developments. The brazen attack, which the Biden administration blames on Iranian-based proxies, adds another layer of complexity to an already tense West Asian situation as the Biden administration tries to keep the Israel-Hamas war from expanding into a broader regional conflict.

“The President and I will not tolerate attacks on US forces, and we will take all necessary actions to defend the US and our troops,” defence secretary Lloyd Austin said on Monday as he met at the Pentagon with NATO Secretary General Jens Stoltenberg.

Biden faces a difficult balancing act as he looks to strike back against Tehran in a forceful way without allowing the Gaza conflict to further metastasize. The drone attack was one of dozens on US troops in West Asia since Hamas launched attacks on Israel on Oct. 7, igniting the war in Gaza. But it’s the first in which American service members have been killed.

National Security Council spokesman John Kirby reiterated a day after Biden promised to “hold all those responsible to account at a time and in a manner (of) our choosing” that the US administration wasn’t seeking to get into another conflict in West Asia.

But Kirby also made clear that the American patience has worn thin after more than two months of attacks by Iranian proxies on US troops in Iraq, Syria and Jordan and on the US Navy and commercial vessels in the Red Sea.