A bomb planted in a rickshaw has killed at least 12 people in Quetta in south west Pakistan, officials say.
At least 10 of the dead were said to be security personnel. A number of other people were wounded.
"The target was a truck of Balochistan Constabulary which was carrying the security personnel," police official Fayyaz Sumbal said.
Quetta, the capital of Balochistan province bordering Afghanistan and Iran, is plagued by sectarian violence.
Sumbal said Thursday's explosion, which destroyed the police vehicle as it travelled through the outskirts of the city, was caused by a remote-controlled bomb.
It was not immediately clear who was behind the blast.
The Pakistan government boosted security in Quetta earlier this year, after a series of attacks on the city's Shia minority.
At least 120 people were killed in a twin suicide bomb attack on a crowded snooker club in January.
And dozens more died in an explosion at a crowded market place in the city on 17 February.
Most of those who died were from Pakistan's Hazara Shia community. Hundreds of ethic Hazaras in Quetta have been killed in such attacks over the last several years.