U.S. Embassy spokesman Joe Mellot told RFE/RL that confirmed that the U.S. ambassador was not in three-vehicle convoy when it was attacked on the highway linking Kabul and the eastern city of Jalalabad.
"A suicide bomber driving a car rammed into the convoy of foreigners passing by Puli Charkhi district," Kabul police official Ali Shah Paktiawal told journalists. "The bomber was killed and his car destroyed. Two of the vehicles belonging to the foreigners were destroyed at the scene. This is all we know about the causalities so far. Our investigation is continuing."
Kabul police later confirmed that the blast killed a 15-year-old Afghan boy.
The attack comes as Taliban insurgents have been stepping up attacks following a winter lull, with at least nine suicide bombings reported in the past week.
(with material from AP, AFP, Reuters)