Islamabad, Pakistan (CNN) -- For the second time in two days, a deadly blast shook a northwest Pakistani city as worshippers marked the sacred holiday of Ashura.
The explosion occurred near a Shiite Muslim procession in Dera Ismail Khan. The bomb was planted inside a bicycle repair shop, killing five people and injuring more than 70 others, said Mian Iftikahr Hussain, the provincial information minister.
A spokesman for the Pakistani Taliban said the group was behind Sunday's bombing on the procession and warned of more attacks.
A day earlier, the Pakistani Taliban claimed responsibility for a blast that killed seven people, including three children, during a Shiite religious procession in the same city Saturday.
That bomb was planted in a garbage container and exploded as the last section of the procession, in which children were following adults, was passing by, police spokesman Khalid Sohail said.
Eighteen people, including five children and two police officials, were wounded in Saturday's attack.
The spokesman for the Pakistani Taliban, Ihsanullah Ihsan, said the group would continue "its mission" and attack Shiite Ashura processions across Pakistan.
Pakistan has been on high alert because of the two-day holiday of Ashura, in which believers mourn the death of a key imam from the 7th century. The government increased security for the Ashura observance.
Shia Islam is a minority sect in the mainly Sunni Muslim country, and its members face persecution from extremists.
The Pakistani Taliban took responsibility for similar attacks earlier this week.
Interior Minister Rehman Malik temporarily blocked cell phone services in cities, where gathered intelligence indicated the possibility of bombs detonated by cell phone. He also banned motor bikes, often used to conceal bombs, for two days in some cities.
Malik said the safeguards were specifically meant to protect Shiites.
Despite heightened security, at least 31 people were killed and 68 wounded in multiple bomb attacks Wednesday.
A Taliban spokesman said those attacks targeted Shiites, whom the terrorists believe denigrate the Prophet Mohammed with their religious observance.
Ashura commemorates the death of the Prophet Mohammed's grandson, killed in the Battle of Karbala in 680 AD. The battle and subsequent death of Imam Hussein caused the split between Shiite and Sunni Muslims.