A suicide bomber in a car hit an Afghan army convoy in western Afghanistan on Wednesday, killing two troops, a defense ministry spokesman said. The bomber blew up his car near army vehicles traveling about 30 kilometers outside the city of Herat, said Gen. Mohammad Zahir Azimi, the Defense Ministry spokesman. Three other troops were wounded. The blast was the third suicide car bomb attack in Afghanistan in five days. On Monday, a driver blew up his car near the gates of a US base in the east, killing one Afghan civilian. This followed an attack in the capital Saturday that killed five people, including one American soldier.