A suicide car bomber killed at least three foreign servicemen during an attack on a convoy near the U.S. embassy in Kabul on Tuesday, including two Americans, according to a U.S. defense official. The official did not say whether they were civilians or soldiers. The Polish army also reported a casualty. It was one of the worst attacks on international forces in Afghanistan's capital in months. Five service members and at least a dozen Afghans were wounded in the blast. The Taliban claimed responsibility for the attack, which occurred on the main road leading to Kabul's international airport. The group said one of its operatives, referred to only as Bilal, had been lying in wait for foreign troops in a car packed with explosives. “It was a very powerful blast and happened just as the vehicles sped out of the embassy,” said eyewitness Taj Mohammad. A fourth soldier died in a separate attack involving an a man wearing an Afghan soldier's uniform firing on NATO forces. It echoes the attack that occured on August 5, which killed two-star U.S. Army Maj. Gen. Harold J. Greene.