A suicide bomber killed himself and a policeman after police stopped him in a northwestern Pakistani town today.
"The attacker refused to be checked and detonated his explosives," said a senior police official in the town of Dera Ismail Khan, where the blast occurred. Seven people were wounded, he said.
The explosion - the third in Pakistan since Friday - came as police across the country were on high alert for sectarian attacks during Shia Muslim ceremonies this week.
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 Shia minority mourns the death of one of the heroes of its sect, which culminates on Tuesday.