U.S. Central Command said the strike took place in Nangarhar province, east of Kabul and bordering Pakistan.

“Initial indications are that we killed the target. We know of no civilian casualties,” a U.S. military statement said. It did not say whether the target was connected with the airport attack.

President Joe Biden vowed on Thursday that the United States would hunt down those responsible for the attack, saying he had ordered the Pentagon to come up with plans to strike at the perpetrators.

A reaper drone, which took off from the Middle East, struck the militant while he was in a car with an  Islamic State associate, the official said. Both are believed to have been killed, a U.S. official added.

Islamic State Khorasan (ISIS-K), an affiliate of militants who previously battled U.S. forces in Syria and Iraq, said it had carried out Thursday’s attack, which killed dozens of people – including Afghans who were trying to leave the country.In addition to the 13 U.S. troops killed, 18 injured were flown to Germany.

There are roughly 5,000 U.S. troops at Kabul’s airport, helping to evacuate American citizens, at-risk Afghans and other nationalities before Biden’s Tuesday deadline.