Capt. Bill Salvin, a spokesman for the American military in Kabul, said three American soldiers were wounded in the blast but their injuries were not believed to be life-threatening.

“The convoy was traveling in mine-resistant vehicles. One vehicle was damaged but was still operational,” Captain Salvin said.

An affiliate of the Islamic State claimed responsibility for the attack. The group, largely made up of former members of the Pakistani and Afghan Taliban, has carried out multiple deadly attacks in Kabul and continues to have a presence in eastern Afghanistan, where Afghan and American soldiers are currently carrying out an operation against them. Last month, the United States dropped its largest conventional bomb on a cave complex held by the group in Nangarhar Province.

But the Taliban still remain Afghanistan’s largest security concern, and the attack comes amid fears of escalating violence as the resurgent group has begun another spring offensive.

In announcing Operation Mansouri, named after their former supreme leader, Mullah Akhtar Muhammad Mansour, who was killed in an American drone strike in Pakistan, the Taliban vowed to take control of more territory through “conventional attacks, guerrilla warfare, complex martyrdom attacks, insider attacks” and the use of homemade bombs.

What complicates the violence is the fear, expressed by Afghan and Western security officials, of a possible convergence between the Islamic State and elements of the Taliban. Officials say the attacks, particularly in the urban centers, often bear the hallmarks of the Haqqani network, which is part of the leadership of the Taliban council operating out of Pakistan.

The violence continues to take its toll on Afghan civilians. The United Nations mission in Afghanistan has documented 2,181 civilian casualties in the first quarter of 2017, with 715 deaths and 1,466 injuries. Compared with last year, that is a 2 percent decline in civilian deaths, but a 5 percent increase in injuries, the United Nations said last week.