MAIDUGURI, NIGERIA, Dec 25 - At least 5 worshippers were killed and 35 others injured when a suspected suicide bomber detonated an explosive inside a mosque in Maiduguri, the capital of Nigeria's Borno state, during evening prayers, police said.

No group has claimed responsibility for Wednesday's attack, which comes amid heightened security concerns in Nigeria’s northeast, where Islamist insurgents Boko Haram and its ISWAP faction have waged a 15-year campaign of violence targeting civilians, mosques, and markets.