ISLAMABAD, Pakistan (CNN) -- An explosion at the funeral Friday of a district police officer killed earlier in the day in northwest Pakistan killed 30 people and injured between 50 and 55, province police said.
The Swat special branch of police could not confirm reports that the blast, which occurred in Mingora, Swat's capital, was from a suicide bomber.
The district police officer was killed by an explosion Friday in a separate area of northwest Pakistan.
Interior Ministry spokesman Javed Iqbal Cheema said the attack was probably the work of militants operating in Swat and the Federally Administered Tribal Areas, which have long been havens for foreign fighters.
No one has claimed responsibility for the attack. Watch scenes of the deadly attack »
Earlier Friday, a bomb in Lakki Marwat, also in northwest Pakistan, killed the district superintendent of police for whom the funeral was being held, according to the Web site of the country's Office of Inter-Services Public Relations.
The district superintendent's driver was also killed in the explosion, the Web site said.
On Monday, a suicide bomber in Rawalpindi killed Pakistan's surgeon general, Lt. Gen. Mushtaq Ahmad Baig, along with his driver and five civilian bystanders, according to a military news release.
The attacker, who detonated his bomb near Pakistan's military headquarters, also died.
Baig had assumed the surgeon general post only a year ago. E-mail to a friend