Pakistani policemen attend a funeral ceremony for policemen killed in a bomb blast in southwest Pakistan's Quetta, May 23, 2013. At least 12 people including 10 security men were killed and 17 others injured when a bomb hit security forces' vehicle in Pakistan's southwest Quetta city on Thursday morning, local officials said. (Xinhua/Mohammad)

Pakistani policemen attend a funeral ceremony for policemen killed in a bomb blast in southwest Pakistan's Quetta, May 23, 2013. At least 12 people including 10 security men were killed and 17 others injured when a bomb hit security forces' vehicle in Pakistan's southwest Quetta city on Thursday morning, local officials said. (Xinhua/Mohammad)

Pakistani policemen carry a coffin during a funeral ceremony for policemen killed in a bomb blast in southwest Pakistan's Quetta, May 23, 2013. At least 12 people including 10 security men were killed and 17 others injured when a bomb hit security forces' vehicle in Pakistan's southwest Quetta city on Thursday morning, local officials said. (Xinhua/Mohammad)

Pakistani policemen carry a coffin during a funeral ceremony for policemen killed in a bomb blast in southwest Pakistan's Quetta, May 23, 2013. At least 12 people including 10 security men were killed and 17 others injured when a bomb hit security forces' vehicle in Pakistan's southwest Quetta city on Thursday morning, local officials said. (Xinhua/Mohammad)

A Pakistani policeman comforts a mourner during a funeral ceremony for policemen killed in a bomb blast in southwest Pakistan's Quetta, May 23, 2013. At least 12 people including 10 security men were killed and 17 others injured when a bomb hit security forces' vehicle in Pakistan's southwest Quetta city on Thursday morning, local officials said. (Xinhua/Mohammad)