Pakistani Shiite Muslims search the wreckage of a destroyed pilgrims bus after a bomb attack at Dringhar village on the Pakistan-Iran highway some 60 kilometres west of Quetta, Baluchistan's capital on January 21, 2014.
A Pakistani police officer says a bomb rigged to a bicycle has hit a police patrol on its way to guard a polio vaccination team, killing six policemen and a boy.
The officer, Shafiullah Khan, says the bombing took place on Wednesday morning in the Charsadda district in the country's northwest.
Khan says the bomb, which was set off by remote control, struck close to a busy town market. The blast also wounded 11 people.
The killed boy was just a bystander.
The bombing came just hours after a car bomb hit a bus carrying Shiite pilgrims in a restive region of southwest Pakistan, killing 20.
And on Tuesday, three health workers were killed in an attack on a polio vaccination team in southern city of Karachi.