Four worshippers, including a senior cleric, were injured when a bomb exploded during Friday prayers at a mosque in northwest Pakistan's Khyber Pakhtunkhwa province, police said.

District Police Officer Asif Bahader said an improvised explosive device (IED) exploded at Maulana Abdul Aziz Mosque in South Waziristan, injuring Jamiat Ulema-e-Islam (JUI) district chief Maulana Abdullah Nadeem among others.