Islamabad, Pakistan (CNN) -- The Pakistani Taliban claimed responsibility Saturday for a blast that killed seven people, including three children, during a Shiite religious procession.
The bomb was planted in a garbage container in the central Pakistani city of Dera Ismail Khan 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 the attack.
The spokesman for the Pakistani Taliban, Ihsanullah Ihsan, said the group would continue "its mission" and attack Shiite Ashura processions across Pakistan.
Pakistan is on high alert because of the two-day high holy Shiite holiday of Ashura, in which believers mourn the death of a key imam from the seventh century.
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.
The government increased security for the Ashura observance, which ends Saturday.
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.
At least 31 people were killed and 68 wounded in multiple bomb attacks Wednesday despite heightened security.
A Tehrik-i-Taliban spokesman said those attacks targeted Shiites, who 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.