About 120 Afghan lawmakers quit parliamentary proceedings to condemn the Sunday killings of civilians, including women and children in the Panjwai district in southern Kandahar province, Khaama Press reported.
The Parliament members demanded a public trial and called for the setting up of a commission to investigate the shootings, the report said.
U.S. officials have warned of reprisal attacks over the shootings, which came just three weeks after the inadvertent burnings of Koran, the holy text of Muslims, at a U.S. base, the report said.
The Koran burning triggered deadly protests.
The Taliban have vowed to avenge Sunday's killings, the report said.