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Washington on Tuesday appeared primed to order retaliatory strikes against Iran-backed militias after three American troops were killed in Jordan.
That was despite one prominent Iraqi Shiite group ordering its forces to stop attacking US personnel.
President Joe Biden said he has decided how he will respond to Sunday's drone strike in north-east Jordan and blamed Iran for supplying weapons used in the attack.
Mr Biden did not go into details but stressed he did not want to see broader war in the region.
“I do hold [Tehran] responsible in the sense that they're supplying the weapons to the people who did it,” Mr Biden told reporters.
“I don’t think we need a wider war in the Middle East. That’s not what I’m looking for.”
The Islamic Resistance in Iraq, an umbrella title for pro-Iran groups, claimed responsibility for Sunday's attack that killed three US troops and injured about 40 when a drone struck the barracks of a remote base in Jordan.
Kataib Hezbollah, an armed group with close ties to Iran, has been the main focus of blame for the attack.
On Tuesday the group announced the suspension of all military operations against US troops in the region.
In a statement, the group said the decision had been made to prevent “embarrassment” to the Iraqi government.
Iraqi Prime Minister Mohammed Shia Al Sudani is under intense domestic pressure to force US-led coalition forces to leave Iraq, a decade after their arrival to help fight ISIS.
Mr Al Sudani's critics say US strikes in Iraq are a breach of Iraqi sovereignty, so more action could undermine him.
Pentagon spokesman Maj Gen Pat Ryder appeared sceptical about the Kataib Hezbollah instruction for its fighters to stand down.
Maj Gen Ryder said there had been at least three other Iran-linked strikes in Iraq and Syria since Sunday's attack in Jordan, and more than 160 in recent months.
“Actions speak louder than words,” he told reporters.
He said Central Command is still assessing how the drone had passed US air defences around the Jordanian base.
Several US outlets have reported that it might have been misidentified as a returning US drone.
The attack marked the first time US personnel have been killed in an enemy strike in the region since the Israel-Gaza war began, marking a significant escalation.
It has also created another headache for Mr Biden, who is running for re-election.
Asked if a direct link to Iran has been established, he said: “We'll have that discussion.”
Iran has publicly denied involvement in the attack.
Maj Gen Ryder said he would not give clues as to any future US military operation, but stressed: “There will be consequences."
The Biden administration faces a balancing act as it decides on its response.
If the President overreacts, he could provoke a new round of retaliatory strikes and a further broadening of the Israel-Gaza war that has already included violence in Yemen, Lebanon, Iraq, Syria and now Jordan.
If Mr Biden does not go far enough, hawkish Republicans will pressure him for appeasing Iran.
Some in Congress have even called for him to launch direct strikes on Iran.
Speaking to reporters on Air Force One, National Security Council spokesman John Kirby said US retaliation could involve more than one strike.
“It's fair for you to expect that we will respond in an appropriate fashion, and it is very possible that what you'll see is a tiered approach here, not just a single action,” he said.
Secretary of State Antony Blinken said on Monday that the response “could be multi-levelled, come in stages, and be sustained over time”.
The attack on Saturday occurred on Tower 22, a US outpost on the Iraq-Syria-Jordan border, where about 350 troops are stationed.
Air-defence systems at the tower had thwarted two attacks in the past months, a US defence official said.
At least 40 US troops were injured in the attack, with eight evacuated for medical care. One was in a critical but stable condition, Maj Gen Ryder said.
Mr Kirby said the President had spoken to the families of the soldiers who died and that he would attend the “dignified transfer” of their bodies to an Air Force base in Delaware on Friday.
