The driver of a car packed with explosives rammed into a U.S. military convoy in downtown Kabul on Friday, killing himself and at least 18 other people, including two American soldiers. Two other American soldiers were among 31 people wounded.

The blast, near the U.S. Embassy in Kabul, came as NATO chiefs appealed for member nations to send reinforcements to combat resurgent Taliban militants. A top British general said the fighting in volatile southern Afghanistan was now more ferocious than in Iraq.