In flared up sectarian violence in Pakistan, three persons were killed in a suicide bombing near a police check-post in North West Frontier Province on Monday where a dozen others were injured in a rocket attack on a mosque despite heavy security during Muharram.

A suicide bomber attempting to target a Shiite Muharram process in Dera Ismail Khan detonated the explosives strapped to his stomach after policemen tried to frisk him at a check-post near Liaqat Park, police said.

"He was wearing a shawl and when he realized he had been stopped he blew himself up," Aslam Khattack, a senior police official, said.

The attacker, a police official and a bystander were killed in the explosion while seven people, including two policemen, were injured.

In another incident, 12 persons were injured, two of them seriously, in a rocket attack at a Shia mosque in Bannu, the home town of North West Frontier Province Chief Minister Muhammad Akram Durrani.

Monday's suicide bombing is the third to rock the country since January 26, when a bomber blew himself up while trying to force his way into Marriot hotel hours before Indian High Commission held a Republic Day reception.      

The bombings by suspected Sunni extremist groups were taking place despite Pakistan throwing a heavy security blanket to check sectarian attacks during the Muharram period.