A suicide bomber has killed five people at a political rally in northwest Pakistan.

Monday's attack in the Batgram district of Khyber-Pakhtunkhwa province took place before a senior member of the Pakistan Muslim League-Q party was scheduled to speak at the gathering. The politician, Ameer Muqam, had not yet arrived at the venue.

Two police officers and three civilians were killed in the blast. Another 20 people were wounded.

Elsewhere in Pakistan, an explosion ripped through an army weapons depot near Islamabad, wounding at least three people.

Police said the cause of the blast was accidental.

Militants linked to al-Qaida and the Taliban have stepped up suicide and bomb attacks across Pakistan since the killing of Osama bin Laden by U.S. Navy Seals in early May.