Washington said it was “not looking for a war with Iran” on Monday, a day after it blamed Tehran-backed militants for a drone strike that killed three US soldiers and wounded dozens of others.

The attack on a military base in north-east Jordan, near the Syrian border, was the first to kill US troops since the Israel-Hamas war triggered a wave of assaults by Iranian-aligned groups against American forces in the region.

“We are not looking for a war with Iran,” US National Security Council spokesman John Kirby told NBC’s Today Show. But he added: “We’ll keep looking at the options . . . We want these attacks to stop.” 

Kirby’s comments came after Iran sought to distance itself from the deadly attack, with both sides appearing keen to avoid a further escalation.

Iran’s foreign ministry labelled any accusation that it was involved in the US troops’ deaths as a “baseless” conspiracy by those “interested in dragging the US into a new conflict in the region to intensify the crisis”.

Tehran’s mission to the UN depicted the strike as part of clashes “between the US army and resistance groups in the region, who reciprocally confront each other”.

Washington has hit targets linked to Iranian-backed militias across the region following more than 160 attacks by militants on US troops in Iraq, Syria and Jordan since October, as well as 30 strikes on international shipping in the Red Sea.

To date it has not struck Iran directly — although, in reference to the deaths of three American service members, Kirby said: “We’re now in different territory.”

Kirby said the US was “still working our way through” attributing responsibility for Sunday’s drone attack. But he added that Washington believed the group involved was supported by Kataib Hizbollah, an Iranian-backed Iraqi militia.

US defence secretary Lloyd Austin said Washington would “take all necessary actions to defend the US and our troops”.

American forces in Syria and Iraq have come under repeated assault by a newly created group of Iran-backed Iraqi militias known as the Islamic Resistance in Iraq (IRI), which says it is retaliating over Washington’s backing for Israel’s war against Hamas in Gaza.

Sunday’s attack, which US defence officials said also injured at least 34 service members, struck the Tower 22 outpost near Jordan’s border with Syria, which houses 350 US military personnel as part of the coalition against Isis.

The US has about 2,500 troops in Iraq and about 900 in Syria, where they are deployed to help prevent a resurgence of the jihadist group.

The IRI said on Sunday it used armed drones to attack three military bases with US personnel in Syria, including one across the border from the Tower 22 outpost. It was not clear if that was the attack that killed the three US troops.

Top Republicans in Congress have called for direct strikes on Iran in response.

“Hit Iran now. Hit them hard,” senator Lindsey Graham wrote on X, while senator John Cornyn wrote: “Target Tehran.”

In a posting on his Truth Social network, former president Donald Trump labelled the attack a “horrific and tragic consequence of [President] Joe Biden’s weakness and surrender” but called for no specific action. “We are on the brink of World War 3,” he added.

Jonathan Panikoff, a former senior intelligence official now at the Atlantic Council, said Iran was “probably calculating that the US is reticent to respond and engage in a region-wide conflict”.

He added: “The facts on the ground demonstrate that avoiding the regional conflict is becoming harder regardless of US desires, and the US is now a prime target.”

Oil prices briefly climbed more than 1 per cent in early trading on Monday, before falling back.

Brent crude, the international benchmark, was 0.7 per cent lower at $82.94 a barrel later in the day. The equivalent US benchmark West Texas Intermediate fell 0.9 per cent to trade at $77.29 a barrel.

Iran’s foreign ministry spokesperson Nasser Kanaani accused the US of supporting “genocide” against Palestinians in Gaza, as well as attacks against anti-Israel groups in Iraq, Syria and Yemen, which he said were “exacerbating this cycle of instability”.

Tehran demanded “an immediate ceasefire” that “can pave the way for the return of calm to the region”, he said.

On Monday, Syria accused Israel of launching an air strike targeting areas south of Damascus. Syria’s defence ministry said civilians were killed and injured, without specifying numbers, in a statement published by SANA, the state news agency.

An initial report by SANA said the dead included “Iranian advisers”, but the reference was later removed. Tehran’s ambassador to Syria, Hossein Akbari, dismissed reports of Iranian casualties, saying on X: “In today’s attack . . . no advisory centre of the Islamic Republic of Iran was targeted.”

This month, the US military killed a high-ranking commander of Harakat al-Nujaba, an Iran-backed militia in Iraq. Washington described the action as “self-defence” after the faction conducted attacks on US personnel. Experts believe Harakat al-Nujaba is one of the IRI’s most influential factions.

The US and UK have also been co-ordinating joint strikes on Houthi targets in Yemen in response to the Iran-backed rebels’ attacks on vessels in the Red Sea, a critical shipping lane for global trade.

The Houthis have said their attacks on shipping lanes were in response to Israel’s bombardment of the Gaza Strip since it launched its war against Hamas in October.

Additional reporting by William Sandlund in Hong Kong