A damaged U.S. military vehicle is seen at the site of a suicide bomb attack in Kabul on May 3. (Mirwais Harooni/Reuters)

A suicide bomber rammed a car filled with explosives into an armored NATO convoy in the Afghan capital Wednesday morning, killing eight Afghan civilians and wounding 28, including three coalition soldiers, health officials said.

The Islamic State asserted responsibility for the attack, which occurred at rush hour on a crowded boulevard a few hundred yards from the U.S. Embassy and several Afghan government ministries.

A news agency affiliated with the militant group claimed the attack killed eight American troops. But officials with the U.S.-led international force here said that no coalition troops were killed and that the injuries to the three soldiers were “non-life-threatening.” Several injured civilians, however, were reported to be in critical condition.

The explosion shattered glass in numerous buildings and left several disabled and damaged vehicles stranded along the busy thoroughfare.

A smoldering, partially crumpled minivan at the site was reported to be the vehicle used in the blast.

An Afghan victim injured in a suicide attack receives oxygen as he is treated at the Wazir Akbar Khan hospital in Kabul on May 3. (Wakil Kohsar/AFP/Getty Images)

The Islamic State has claimed numerous attacks in Kabul in the past year, including a devastating assault March 8 on a large military hospital that killed about 50 people. The assailants entered the high-security compound disguised as medical personnel.

Wednesday’s bombing also followed a slew of attacks by rival Taliban insurgents, who continued their aggressive campaign against the Afghan state all winter and last week announced a new spring offensive.

Record numbers of civilian and military casualties were registered last year in the protracted conflict, which has stretched Afghan forces thin. The growing presence of the Islamic State in the country in the past two years has only exacerbated the strain on the Afghan military, which is struggling to confront the militant threat with drastically reduced support from the United States and other international partners. 

The Special Inspector General for Afghanistan Reconstruction said in a quarterly report to Congress that “security is the most obvious and urgent challenge” to rebuilding the country.