WASHINGTON — President Joe Biden Thursday vowed to complete the evacuation of Americans and their allies from Afghanistan after a deadly terror attack near Kabul’s airport took the lives of a dozen U.S. service members and many Afghans.

“We will not be deterred by terrorists. We will not let them stop our mission. We will continue the evacuation,” Biden said from the White House. “We will rescue Americans, we will get our Afghan allies and the mission will go on. America will not be intimidated.”

The U.S. has about 5,400 military personnel assisting with the emergency evacuation efforts in Kabul.

U.S. Marine Gen. Kenneth McKenzie, commander of U.S. Central Command, said 11 U.S. Marines and one Navy medic were killed and 15 were wounded after two suicide bombers detonated explosives.

McKenzie, who oversees America’s military operations in the region, also said that a number of Afghan civilians were also killed in the blast, but was not able to provide a precise number. He added that the current U.S. military assessment is that the bombers were ISIS fighters.

ISIS has claimed responsibility for the attack.

The president addressed those responsible for the attack saying, “We will not forgive, we will not forget, we will hunt you down and make you pay.”

“I’ll defend our interests and our people with every measure in my command,” Biden said.

“I’ve also ordered my commanders to develop operational plans to strike ISIS-K assets, leadership and facilities. We will respond with force and precision at our time at the place we choose and at the moment of our choosing,” he said, indicating that the U.S. had leads on the ISIS leaders who ordered the attack.

“We have some reason to believe we know who they are,” Biden said, though he noted that the U.S. was not certain. “And we will find ways for our choosing, without large military operations, to get them. Wherever they are.”

The president had previously warned on Tuesday that staying longer in Afghanistan carried serious risks for foreign troops and civilians. He has said that ISIS-K, an Afghanistan-based affiliate of the terror group, presented a growing threat to the airport.

“I’ve repeatedly said this mission was extraordinarily dangerous and that’s why I’ve been so determined to limit the duration of this mission,” Biden reiterated on Thursday.

Earlier in the week, the president told leaders of the G-7, NATO, United Nations and European Union that the United States will withdraw its military from Afghanistan by the end of the month.

In the last 24 hours, Western forces evacuated 13,400 people out of Kabul on 91 military cargo aircraft flights. Since the mass evacuations began on Aug. 14, approximately 95,700 people have been airlifted out of Afghanistan.

About 101,300 people have been evacuated since the end of July, including about 5,000 U.S. citizens and their families.

A State Department spokesperson said Thursday that the U.S. is now in contact with about 1,000 Americans believed to be in Afghanistan.

“The vast majority – over two-thirds – informed us that they were taking steps to leave,” the spokesperson added.