A large blast shook a road near the U.S. Embassy and an American military base in Afghanistan's capital on Thursday, killing at least two people. The blast hit about 12:10 p.m. local time and smoke could be seen rising from the site soon after. An Associated Press reporter saw two bodies on the ground, both burned and later covered with plastic sheets. It was not immediately clear what caused the explosion. At least six vehicles were burned, including at least one Humvee with an Italian flag painted on the side. Sirens rang through the area as emergency vehicles arrived. U.S. military spokeswoman Capt. Elizabeth Mathias said they were aware of the blast but did not have more information.