A homicide bombing cell is operating in the Afghan capital with the aim of targeting foreign troops, the U.S. military said Sunday.

The statement came two days after a homicide car bomber rammed into a U.S. military convoy near the U.S. Embassy in Kabul, killing 16 people, including two American soldiers. The Taliban claimed responsibility for the bombing, which was the deadliest homicide attack in the capital since the fall of the hard-line Taliban in late 2001.

Col. Tom Collins, the chief U.S. spokesman, said the coalition was aware that a bomber was in the city before the bombing, but lacked a description of the attacker or the vehicle he was using.

"The coalition had intelligence that a suicide bomber was lurking in Kabul. What we didn't have was a description of the attacker or license plate for his vehicle, but somehow I believe somewhere out there someone knew this guy and had information that could have saved a lot of lives that day had they reported it," he said.

Collins said he couldn't give further details about the suicide bombing cell, but said it was still working and "remains very much a threat."

"Through our intelligence sources we know there's a cell here in Kabul, at least one, whose primary mission is to seek coalition or international troops and hit them with suicide bombs," he said at a news conference.