ISLAMABAD, Pakistan, Aug. 19 (UPI) -- Taliban militants in the tribal areas of northwest Pakistan claimed responsibility for a suicide attack Tuesday that left at least 25 dead, officials said.

A suicide bomber detonated his explosive vest inside the emergency room of the hospital in Dera Ismail Kahn in the North-West Frontier province. Shiite mourners had gathered outside the hospital as the body of a local leader, Zaffar Jajjee, was slain in an earlier shooting.

Local officials said as many as 25 died in the blast, including two policemen, the Press Trust of India reported.

Tehrik-e-Taliban Pakistan, an umbrella group of pro-Taliban groups in northwest Pakistan, claimed responsibility for the attack in response to military operations in the tribal areas along the border with Afghanistan.

Maulvi Omar, a spokesman for the group, said there would be further attacks if Pakistani officials did not halt their raids on the area.

The bombing comes a day after Pervez Musharraf resigned as president of Pakistan.