KANDAHAR, Afghanistan – A roadside bomb exploded Saturday as a Canadian armored vehicle drove by, killing four soldiers, the Canadian military said.

The attack occurred at about 7:30 a.m. as Canadian forces patrolled the Shah-Wali-Kot district village of Gomboth, about 25 miles north of Kandahar, Canadian military spokesman Lt. Mark MacIntyre said.

Most of Canada’s 2,200 troops in Afghanistan are based in Kandahar, where they have taken over security from U.S. forces.