Biden said US would hunt down Kabul airport attackers. A day later, a drone strike killed two ISIS-K targets.

WASHINGTON – President Joe Biden warned those behind a deadly terrorist attack that killed and wounded American service members and Afghan civilians in Kabul on Thursday that the U.S. would “hunt you down and make you pay.”

A day later, he followed through on that threat.

A military drone strike Friday killed two "high-profile" members of ISIS-K and wounded a third, the first American attack on the terrorist group following a bomb attack at Hamid Karzai International Airport, the Pentagon said Saturday.

The Pentagon's initial announcement of the strike said one ISIS-K member had been killed. Military officials updated the death toll Saturday.

Those killed were ISIS-K "planners and facilitators," said Army Maj. Gen. William D. “Hank” Taylor, joint staff deputy director for regional operations. Their names were not made public.

Biden met with his national security team at the White House on Saturday and, afterward, warned that another attack was likely in the coming days.

"The situation on the ground continues to be extremely dangerous, and the threat of terrorist attacks on the airport remains high," he said in a statement. "Our commanders informed me that an attack is highly likely in the next 24-36 hours. I directed them to take every possible measure to prioritize force protection."

Biden vowed to avenge any additional attacks. "Whenever anyone seeks to harm the United States or attack our troops, we will respond," he said. "That will never be in doubt."

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Thirteen U.S. service members – 11 Marines, a Navy corpsman and an Army soldier – and at least 169 Afghan people died in Thursday's airport bombing, which unfolded as American and allied forces were scrambling to evacuate people from Afghanistan.

The attack – one of America's deadliest days in the nearly 20-year war in Afghanistan – drew fierce censure from Republicans, stoked fears about the final days of America's evacuation mission and threatened to define Biden's still-young presidency as one of chaos instead of the competence he promised on the campaign trail.

The bombing came five days before  the Aug. 31deadline that Biden set for withdrawing U.S. troops and amid warnings that more terrorist strikes could come soon.

ISIS-K claimed responsibility for the attack.

More:Afghanistan latest: Pentagon says US drone strike kills ISIS-K planner one day after Kabul airport bombing

Wounded Afghans lie on a bed at a hospital after an attack on the airport in Kabul, Afghanistan, on Aug. 26.

Even before the bombing, Biden was facing harsh criticism over his strategy for winding down the war that started in 2001 when the United States invaded Afghanistan, which sheltered the terrorists who carried out the 9/11 attacks on the World Trade Center and the Pentagon.

Just hours after the attack Thursday, a somber Biden called the American service members killed “heroes” and promised to exact revenge on those behind the strike.

"We will not forgive," he said at the White House. "We will not forget."

After the tragedy of the Kabul bombing, Republican lawmakers universally rushed to condemn Biden's handling of Afghanistan while demanding his administration keep troops in the increasingly unstable country past Tuesday's deadline to ensure the safe evacuation of all remaining Americans

Taylor would not provide details of Friday's drone strike, but the Pentagon has said it occurred in the Nangahar Province of Afghanistan.

Military officials believe the ISIS-K officials targeted were involved in planning future attacks. A U.S. official who was not authorized to speak publicly about the attack said Friday one of the targets was killed while traveling in a vehicle with an associate. It was not immediately clear whether the associate was the second target killed.

“The fact that two of these individuals are no longer walking on the face of the earth, that’s a good thing,” Pentagon spokesman John Kirby said.

Officials know of no civilian casualties in the strike, Taylor said.

ISIS-K leadership generally operates in Nangarhar and Kunar provinces in Afghanistan.

ISIS-K considers the Taliban, the Islamic militant group that is noted for its brutality and now controls Afghanistan, to be insufficiently devout in its adherence to Islam. The two militant groups have attacked each other.

More:They made the 'ultimate sacrifice': The US service members killed in Afghanistan airport bombing

Around the same time as the drone strike against the ISIS-K targets, the U.S. Embassy in Kabul issued a fresh warning urging Americans waiting at four airport gates to “leave immediately” because of security threats.

The U.S. Department of State Bureau of Consular Affairs tweeted: "Due to security threats at the airport, we continue to advise U.S. citizens to avoid traveling to the airport and to avoid airport gates. Those at Abbey gate, East gate, North gate or New Ministry of Interior gate should leave immediately."

A State Department spokesperson said the agency would not address intelligence matters, but noted the "dynamic and volatile security situation on the ground" in Afghanistan.

More:'Day of reckoning': GOP unified in blaming Biden for Afghanistan bombing, divided on refugees and next steps

Contributing: Ledyard King