The Taliban have said it carried out a bombing that killed at least five people and wounded more than 90 others at a Shia religious procession in north-west Pakistan on Sunday.

At least 30 people died in five attacks on the minority Muslim sect over the past five days, while about 100 have been wounded in the runup to the annual Ashura holiday, which commemorates the 7th-century death of the prophet Muhammad's grandson. The schism between Sunni Muslims and Shias dates to that time.

The explosion occurred as hundreds of Shias were passing through the main intersection of Dera Ismail Khan city, a police officer, Abdul Sattar, said. Preliminary investigations suggest a bomb had been planted near a shop along the procession route, he added.

Several of the injured are in a serious condition, said a local hospital official, Faridullah Mahsud, who added that three members of a paramilitary unit providing security were among the injured. Mahsud confirmed the five deaths.

The Pakistani Taliban, a Sunni extremist group, frequently attack Shias, whom they consider heretics. Ashura ceremonies are a prime target as they draw large crowds that march to mourn the martyred Imam Hussein.

Qais Abbas, a witness, said the procession had been passing through the Chogla intersection of the city when the bomb went off. One of his relatives remained in a critical condition, he said, but he and others were moving the wounded to better-equipped hospitals. "Here we are not getting proper care for the injured, there are not enough doctors or medicines," he said.

The same city was hit by a similar bombing on Saturday, which killed seven and injured 30. On Wednesday night, a Taliban suicide bomber struck a Shia Muslim procession in Rawalpindi, a garrison city near Islamabad, killing 17. Also on Wednesday, extremists detonated two bombs outside a Shia mosque in the southern city of Karachi, killing one person and wounding 15 others.

The Pakistani Taliban have claimed responsibility for all the attacks. Its spokesman, Ehasanullah Ehsan, said the group would not relent and "looks forward to more [attacks]".

The authorities have deployed thousands of police officers across the country to bolster security for the holy day. Mobile phone service has been shut down in major cities to prevent further bombings, which officials say often use phones as remote detonators.