The U.S. response to a drone attack that killed three American service members in Jordan last weekend will be carried out "over the course of several days" and striking "multiple targets," a U.S. official told ABC News Tuesday.

"These are going to be very deliberate targets -- deliberate strikes on facilities that enabled these attacks" on U.S. forces, said the official, speaking on condition of anonymity in order to discuss sensitive details.

Officials would not say whether any of the targets would be inside or outside Iran.

Leaving the White House Tuesday morning, President Joe Biden said he had decided how the U.S. would respond to the attack by Iran-backed militants, but gave no more details.

When asked if Iran is responsible, he said Tehran is arming these proxy groups. "I do hold them responsible in that they're supplying the weapons to the people who did it," he said.

At the same time, he told reporters the U.S. is not "looking for" a "wider war in the Middle East."

Details about how an enemy attack drone was able to reach a remote U.S. military base in Jordan were still trickling in Tuesday, as the military continued its investigation.

According to three officials, speaking on condition of anonymity in order to discuss sensitive battlefield details, the one-way enemy attack drone approached the base around the same time as a U.S. surveillance drone, causing confusion and preventing the U.S. from deploying air defenses.

The enemy drone hit the living quarters of the base early in the morning Sunday while troops were still sleeping, wounding at least 40 and killing three.

The Pentagon on Monday announced the names of the three Army reservists killed as Sgt. William Jerome Rivers, 46, of Carrollton, Georgia; Spc. Kennedy Ladon Sanders, 24, of Waycross, Georgia; and Spc. Breonna Alexsondria Moffett, 23, of Savannah, Georgia, all from an Army Reserve engineering unit from Georgia.

The deadly attack, which several officials have described as simple luck by the enemy, is a dramatic escalation in the months-long tension between Iran-backed militants and US forces stationed in Iraq and Syria.

Since mid October, there have been at least 165 attacks on U.S. troops in Iraq, Syria and Jordan. The U.S. has launched several retaliatory strikes, including in Iraq.

In response to the strikes, a spokesperson for the Iranian Mission for the U.N. said late Sunday, "Iran has nothing to do with the attacks in questions. The conflict has been initiated by the United States military against resistance groups in Iraq and Syria; and such operations are reciprocal between them."

Gen. Robert Abrams, a retired combatant commander, said U.S. Central Command, which oversees forces in the region, will be trying to provide several military strike options to the president.

"Biden needs to send a message, but he also doesn't want to escalate the tensions ... That's the hard conversation that is happening right now between the Pentagon, CENTCOM and the White House," Abrams told ABC News Live.

Some Republicans have questioned Biden's strategy in the Middle East so far, suggesting he should attack Iran more directly. Officials ABC News spoke with Tuesday would not say where the U.S. strikes might occur or whether they would target Iranian officials directly.

"We need a major reset of our Middle East policy to protect our national security interests and restore deterrence," House Foreign Affairs Committee Chairman Michael McCaul said in a statement as House Speaker Mike Johnson called for "a crystal clear message across the globe that attacks on our troops will not be tolerated."

In an interview taped last week with ABC's "This Week" co-anchor Martha Raddatz, Gen. CQ Brown, chairman of the Joint Chiefs of Staff, was asked if Americans being killed in the Middle East would impact his decision making.

He said the military was doing "everything we can to protect our forces" and noted the U.S. does not want "broader conflict" in the region -- and that he doesn't believe Iran wants war with the U.S., either.

"We don't want to go down a path of greater escalation that drives to a much broader conflict within the region," Brown said.

Secretary of State Antony Blinken said Monday that the "could be multi-leveled, come in stages, and be sustained over time."

"We've taken steps to defend ourselves and defend our partners, as well as prevent escalation," he added. "And the president has been crystal clear: we will respond decisively to any aggression, and we will hold responsible the people who attacked our troops and do so at a time and place of our choosing."

Biden’s response to Jordan attack is likely to be powerful, but US is wary of triggering a wider war with Iran, officials say.

The US’ response to the drone attack in Jordan that killed and wounded US service members on Sunday is likely to be more powerful than previous American retaliatory strikes in Iraq and Syria, officials told CNN, though the Pentagon and White House are being careful not to telegraph the administration’s plans.

President Joe Biden is under increasing pressure to respond in a way that stops these attacks for good. Iran-backed militants have targeted US military facilities in Iraq and Syria over 160 times since October, and several Republican lawmakers have called for the US to hit inside Iran directly to send a clear message.

But the biggest challenge now for the Biden administration is how to respond to the drone strike – the deadliest attack on US forces in the region since the bombing at Abbey Gate killed 13 US service members in the closing days of the Afghanistan withdrawal – without sparking a regional war.

The US has in recent months carried out several strikes targeting Iranian proxies’ weapons depots in Iraq and Syria. To date, none of those strikes have deterred the militants, whose 165 attacks have injured over 120 US service members across the region since October.

Retired Lt. Gen. Mark Hertling said the deaths of US service members “certainly crossed the president’s red line,” and both officials and analysts are expecting a more robust response that is not necessarily confined to one country or one day. But officials have suggested it is unlikely the US will strike within Iran.

Secretary of State Antony Blinken said the environment in the Middle East is as dangerous as it’s been in the region “since at least 1973, and arguably even before that.”

Blinken added that the US response “could be multileveled, come in stages and be sustained over time.”

The Biden administration could decide to again strike the militant groups in Iraq, Syria or both countries, and could also target the leadership of the regional militias. In at least one case in early January, the US targeted a senior member of Harakat al-Nujaba, an Iranian proxy that has attacked US forces. An offensive cyberattack is another option, officials noted.

A US official said the US is being careful not to be too specific about the origin of the drone or which militants launched it, in order to preserve some element of surprise when the US responds. US officials have said only that the Iranian proxy group Kataib Hezbollah appears to have supported the strike.

“We’re not taking anything off the table,” a US defense official told CNN.

‘We don’t seek a war with Iran’

Still, striking Iran is one of the least likely options at this point, officials said. Biden officials said repeatedly on Monday that the US does not want to go to war with Iran, which would be the likely outcome of a US strike within Iran’s borders.

“We don’t seek a war with Iran. We’re not looking for a wider conflict in the Middle East,” John Kirby, the strategic communications coordinator for the National Security Council, told CNN on Monday. “In fact, every action the president has taken has been designed to de-escalate, to try to bring the tensions down.”

While the US holds Iran ultimately responsible for the attacks given Tehran’s financial and military support for its proxy groups, there are no indications yet that Iran explicitly directed the deadly attack on Sunday or intended it as a deliberate escalation against the US, multiple sources told CNN.

The Iranian government has also denied being involved.

“I don’t think this was intended as an escalation,” said a US official. “It is the same type of attack they’ve done 163 times before and on 164 they get lucky.”

The attack bore many of the hallmarks of the previous 160-plus strikes by the Iran-backed militants, officials said — the only difference being that this one successfully hit a housing container at the US base, called Tower 22, early on Sunday when service members were still in their beds and had little time to evacuate.

The drone also flew low, potentially allowing it to evade the base’s air defenses, and approached the base around the same time as an American drone was returning from a mission. That likely caused confusion and may have delayed a response, officials said.

“We know these groups are supported by Iran, and therefore they do have their fingerprints on this, but I can’t tell you more in terms of who directed it,” Sabrina Singh, deputy Pentagon press secretary, said at a briefing Monday.

Still, if the US attempts to de-escalate through proportionate and limited retaliatory strikes, that could be perceived as weak to Iran and its proxies, said Jon Alterman, the Middle East Program director at the Center for Strategic and International Studies.

“If everything is deliberate and proportionate, it creates an incentive for people to go right up to the red line and to make sure they know exactly where that red line is,” Alterman told CNN.

Iran has spent years investing in its regional proxies, from Hezbollah in Lebanon to the Houthis in Yemen to the militant groups in Iraq and Syria. Tehran has supplied these proxies, informally known as the “axis of resistance,” with money, weapons, training and supplies as it seeks to broaden its influence in the Middle East and pressure the United States to disengage from the region.

“In the last three months, Iran has benefited profoundly from its years of investment in the axis of resistance,” Alterman said. Tehran has watched as anti-US and anti-Israel protests swept across the Middle East after the Israel-Hamas war started. Iran has grown increasingly closer to Russia and China, and Iraqi officials have recently begun to more loudly call for an end to the US military presence in the country.

These are measures of victory for Iran.

“Every message you see talks about the fear of escalation from the administration,” said a former senior military official who has closely followed developments in the region. “We have managed to deter ourselves here.”