Three U.S. troops were among the wounded, a US military official said.
The blast hit at 7:55 a.m. (local time) in Kabul police district 9, near the embassy and Supreme Court, according to interior ministry spokesman Najib Danish.
The convoy targeted was mine-resistant and can withstand ambushes, coalition officials tweeted.
ISIS claimed responsibility for the attack. In a statement posted by its media arm Amaq, the terror group said one of its members targeted "a column of American forces."