WASHINGTON - The United States has launched a drone attack against a planner for the Islamic State (ISIS), the US Central Command said Friday, less than 48 hours after a suicide bombing in Kabul, Afghanistan, killed 13 US service members and some 170 Afghans.

"US military forces conducted an over-the-horizon counterterrorism operation today against an ISIS-K planner," US Central Command Spokesman Bill Urban said in a statement, referring to the terror group affiliated to ISIS that claimed responsibility for Thursday's bombing at Kabul's Hamid Karzai International Airport.

"The unmanned airstrike occurred in the Nangahar Province of Afghanistan. Initial indications are that we killed the target. We know of no civilian casualties," the statement said.

US officials have warned of heightened terror threats to US troops in the aftermath of what was one of the deadliest attacks in the 20-year US-led invasion in Afghanistan.

Pentagon Press Secretary John Kirby told a news conference Friday that "specific credible threats" are believed to exist, "and we want to make sure we're prepared for those" threats.

White House press secretary Jen Psaki echoed the concern over those security threats, saying in a press briefing that American officials believe "another terror attack in Kabul is likely."

Also on Friday, Major General Hank Taylor, deputy director of the Joint Staff For Regional Operations, clarified to reporters that the blast at the Abbey Gate of the Kabul airport involving a sole suicide bomber was the only attack that happened Thursday, correcting earlier reports that a second attack was launched at the adjacent Baron Hotel.

"I can confirm for you that we do not believe that there was a second explosion at or near the Baron Hotel; that it was one suicide bomber," Taylor said. It was not clear the individual killed in the US airstrike was specifically involved in Thursday's bombing.

The US reprisal came after President Joe Biden promised to strike those responsible for the suicide bombing.

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