Three U.S. service members were killed and at least 25 others were injured in a drone attack on an outpost in northeast Jordan near the Syrian border, U.S. Central Command confirmed on Sunday. 

But a senior U.S. defense official told Fox News the injury toll could rise to higher than just 25 Americans. Most, if not all, of those injured and killed are Army soldiers based in Northern Jordan near the Syrian border at a base known as Tower 22, which has been in support of the counter-ISIS mission for year, the official said. 

Some of the 25 plus injured have been medically evacuated from the base, likely to Landstuhl in Germany, according to the official. It is not clear if they were hit while sleeping in the residential compound at the base. Defense Secretary Lloyd Austin is actively engaged in discussions taking place at the White House about how to respond.

‘On Jan. 28, three U.S. service members were killed and 25 injured from a one-way attack UAS that impacted at a base in northeast Jordan, near the Syria border. As a matter of respect for the families and in accordance with DoD policy, the identities of the servicemembers will be withheld until 24 hours after their next of kin have been notified,’ CENTCOM said in a statement. 

‘Updates will be provided as they become available,’ the statement added. 

The White House said President Biden was briefed Sunday morning by Austin, national security adviser Jake Sullivan, and principal deputy national security adviser Jon Finer about the attack, which marked a significant escalation as the first time U.S. troops have been killed by enemy fire in the Middle East since the Israel-Hamas war began.  

U.S. troops long have used Jordan as a basing point, and the attack took place in northeast Jordan near the Syrian border. 

Biden blasted ‘radical Iran-backed militant groups’ in reacting to the attack. 

‘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,’ he said. ‘While we are still gathering the facts of this attack, we know it was carried out by radical Iran-backed militant groups operating in Syria and Iraq.’ 

‘Jill and I join the families and friends of our fallen – and Americans across the country – in grieving the loss of these warriors in this despicable and wholly unjust attack,’ Biden continued. ‘These service members embodied the very best of our nation: Unwavering in their bravery. Unflinching in their duty. Unbending in their commitment to our country – risking their own safety for the safety of their fellow Americans, and our allies and partners with whom we stand in the fight against terrorism. It is a fight we will not cease.’  
 
‘The three American service members we lost were patriots in the highest sense,’ the president said. ‘And their ultimate sacrifice will never be forgotten by our nation. Together, we will keep the sacred obligation we bear to their families. We will strive to be worthy of their honor and valor. We will carry on their commitment to fight terrorism. And have no doubt – we will hold all those responsible to account at a time and in a manner our choosing.’ 

In the wake of the attack, Republicans condemned Biden’s perceived inaction so far and some went further accusing the president of appeasing Iran. 

‘Iran’s proxies have launched over 150 attacks on US troops since October, as the Iran-backed Houthis attack global shipping, and Iran-backed Hezbollah and Hamas attack our ally Israel. The Biden administration’s failed Middle East policy has destroyed our deterrence against adversaries in the Middle East. We need a major reset of our Middle East policy to protect our national security interests and restore deterrence,’ House Foreign Affairs Committee Chairman Rep. Michael McCaul, R-Texas, said. 

‘Enough is enough. The Biden administration’s appeasement of Iran must end. It’s time for clear and decisive action, and Iran must be held accountable for the malign activities of its proxies,’ Sen. Tim Scott, R-S.C., said in a statement obtained by Fox News Digital. 

‘It’s long past time for President Biden to finally hold the terrorist Iranian regime and their extremist proxies accountable for the attacks they’ve carried out against U.S. and coalition forces,’ Rep. Mike Rogers, R-Ala., Chairman of the House Armed Services Committee, said. 

Some 3,000 American troops typically are stationed in Jordan, according to The Associated Press. 

The unnamed U.S. officials cited in several reports say the attack happened at Tower 22, a small outpost in northeast Jordan located close to Al Tanf Garrison in southeastern Syria, where U.S. forces have collaborated with local partners combating Islamic State militants, the Jordanian government reportedly is claiming otherwise. 

Jordanian state television quoted Muhannad al Mubaidin, a government spokesman, as insisting the attack happened outside the kingdom across the border in Syria. 

Reuters also cited al Mubaidin as telling Jordanian public broadcaster al Mamlaka television that the attack had targeted the U.S. Al-Tanf base in Syria.

The conflicting information could not be immediately reconciled. 

Since Israel’s war on Hamas in the Gaza Strip began, U.S. troops in Iraq and Syria have faced drone and missile attacks on their bases, but Sunday’s marked the first U.S. fatalities. 

Syria is still in the midst of a civil war and long has been a launch pad for Iranian-backed forces there, including the Lebanon-based terrorist organization Hezbollah. Iraq has multiple Iranian-backed Shiite militias operating there as well. Jordan, a staunch Western ally and a crucial power in Jerusalem for its oversight of holy sites there, is suspected of launching airstrikes in Syria to disrupt drug smugglers, including one that killed nine people earlier this month, according to the AP.

Fox News’ Sarah Tobianski and the Associated Press contributed to this report.