"As an update to the earlier announcement, the number of U.S. personnel with injuries has increased to at least 34 service members, but we expect this number to fluctuate as service members continue to seek follow-on care," read a statement issued by the US Central Command.

"Eight personnel that received injuries required evacuation from Jordan to higher level care, but they are in stable condition. All other service members are being fully evaluated for follow-on care," the statement said.

The attack occurred at the logistics support base located at Tower 22 of the Jordanian Defense Network.

There are approximately 350 U.S. Army and Air Force personnel deployed to the base, conducting a number of key support functions, including support to the coalition for the lasting defeat of ISIS.

US President Joe Biden reacted to the development and claimed the attack was carried out by radical Iran-backed militant groups operating in Syria and Iraq.

"The three American service members we lost were patriots in the highest sense. And their ultimate sacrifice will never be forgotten by our nation," Biden said in a statement.

"Together, we will keep the sacred obligation we bear to their families. We will strive to be worthy of their honour and valour. 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.," the President said.