U.S. forces in Jordan failed to stop a deadly drone attack on an American outpost in Jordan over the weekend because the drone was approaching at the same time as a U.S. unmanned aircraft was returning to base, apparently leading to confusion whether the incoming unidentified drone was from a friend or foe, military officials said Monday.

As a result, the officials said there was no effort made to shoot down the enemy drone that killed three troops and wounded another 34.

Officials, speaking on condition of anonymity, told VOA that the drone attack on a base called Tower 22, located in northeast Jordan near the borders of Syria and Iraq, was one of four launched at the same time by the Islamic Resistance in Iraq, the umbrella group for Iranian-backed militias. The Islamic group also claimed responsibility for the attack.

The other drone attacks did not hit U.S. targets or were shot down. One U.S. defense official said the U.S. has yet to find evidence that Iran directed the attack.

The military officials’ description of the attack came as U.S. President Joe Biden met in the White House Situation Room with his top national security officials about how to respond.

Earlier, National Security Council spokesman John Kirby told CNN the U.S. is planning a “very consequential” response to the attack.

Kirby said Biden “will respond,” but there was no immediate indication of the scope or timing of an American assault.

Kirby said, however, the U.S. does not “seek a war with Iran. We’re not looking for a wider conflict in the Middle East.”

The deaths in the Saturday night attack were believed to be the first from hostile fire during the nearly four-month-long war between Israel and Hamas militants in Gaza although military officials say American troops have come under fire 165 times throughout the Middle East since October.

Some congressional Republican critics have called on the Democratic president for a direct hit on Iran, but such a strike could quickly lead to a spread of warfare in the Mideast.

Iran’s foreign ministry has denied responsibility for the attack in Jordan. The official IRNA news agency quoted ministry spokesman Nasser Kanaani as saying that the “Islamic Republic of Iran has no role in decisions by resistance groups on how they support the Palestinian nation or defend their people.”

The three service members were not immediately identified, pending notification of their relatives. Biden called them “patriots in the highest sense.”

“We will carry on their commitment to fight terrorism,” Biden said in a statement Sunday. “And have no doubt — we will hold all those responsible to account at a time and in a manner of our choosing.”

Later Sunday, at a campaign event in South Carolina, Biden said, “We shall respond.” He then asked for a moment of silence.

In a statement carried by the official Petra news agency, Jordan condemned the terrorist attack that targeted the U.S. base, where it said U.S. forces “are cooperating with Jordan in countering terrorism and securing the border.”

Jordanian government spokesperson Muhannad Mubaidin expressed condolences to the United States and said the attack “did not result in any casualties among officers of the Jordan Armed Forces.”

Michael Pregent, a senior fellow at the Hudson Institute and an expert in Middle East and North Africa political and security issues, spoke with VOA’s Persian service on Sunday.

“Now we have the death of three Americans and (34) injured and the Biden administration needs to hit the individuals responsible for this, it needs to hit facilities inside of Iran,” Pregent told VOA. “This is the only way to get Iran to stop.”

“I heard some information today from the Pentagon that this is Iran’s attempt to bait us into a war with Iran,” he said. “No, Tehran doesn’t want a war with the United States. But Tehran wants to use its proxies to push the United States out of the Middle East.

“But now a red line has been crossed and the United States needs to respond,” Pregent said.

The attack was one of a string of aerial assaults targeting U.S. troops stationed in the region amid the Israel-Hamas war in Gaza. While the United States has not engaged in the fighting in the narrow territory along the Mediterranean Sea, it has staunchly supported the Israeli effort and rebuffed the demands from some world leaders for an immediate cease-fire.

U.S. officials said, however, they are close to reaching an agreement for a two-month halt in the fighting and the release of the remaining 100 or so hostages held by Hamas in Gaza. The initial Hamas attack on Israel in October killed about 1,200 people, while Gaza officials say Israel’s counteroffensive has killed more than 26,000 Palestinians, most of them women and children.

In his Sunday statement, Biden said, “Today, America’s heart is heavy. Last night, three U.S. service members were killed — and many wounded — during an unmanned aerial drone attack on our forces stationed in northeast Jordan near the Syria border.”

A U.S. Defense Department official said some of the wounded sustained brain injuries that required medical evacuations to hospitals.

VOA’s Jeff Seldin and VOA’s Persian service contributed to this article. Some information for this story came from The Associated Press and Reuters.