Pakistani policeman killed in suicide blast

ISLAMABAD, Jan 29 (Reuters) A suicide bomber set off a device in a northwestern Pakistani town today killing himself and a policeman after police stopped him at a checkpoint, security officials said.

The blast -- the third in Pakistan since Friday -- came as police across the country were on high alert for sectarian attacks during Shi'ite Muslim ceremonies this week.

''The attacker refused to be checked and detonated his explosives,'' said Aslam Khattak, a senior police official in the town of Dera Ismail Khan, where the blast occured.

Seven people were wounded, he said.

On Friday, a suicide bomber killed himself and a guard outside the Marriott Hotel in the capital, Islamabad.

The next day a suicide bomber killed 15 people including a city police chief in the northwestern city of Peshawar.

Police are on alert for sectarian violence during Muharram, when the country's Shi'ite minority mourns the death of one of the heroes of its sect, which culminates tomorrow.

REUTERS BDP BD1757