At least 17 Shiite Muslims are dead after a suicide bomber detonated his explosive vest outside a mosque in a busy market in Parachinar, a Pakistani town in the Kurram tribal region bordering Afghanistan, according to the Associated Press.

Reuters also reported on the bombing, saying that the death toll had reached 21. Both newswires reported that local Taliban commander Fazal Saeed claimed responsibility for the attack.

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"We have targeted the Shiite community of Parachinar because they were involved in activities against us," he told Reuters by telephone from an undisclosed location.

"We also warn the political administration of Parachinar to stop siding with the Shiite community in all our disputes," said Saeed to Reuters during the telephone conversation.

The AP also reported that the Taliban leader justified the attack by saying that the Shiites had been attacking Sunnis.