Security was tightened in the Nigerian city of Maiduguri on Monday after suspected Islamists tossed bombs and fired on a crowded beer garden killing at least 25 people, security sources said. Sunday\'s attack caused one of the single-largest casualty tolls in the troubled northern city in recent months and coincided with the assumption of control of security operations there by a special task force of crack troops and other personnel. A military officer said security had been scaled up in the city following the attack. \"The JTF (joint task force) began operations in Maiduguri yesterday with the deployment of more troops into the city, including 500 navy personnel,\" said a senior military officer who asked not to be named as he does not have clearance to speak to journalists. The unit \"is now in charge of security in the city and the responsibility of combating the spate of attacks in the metropolis is in its hands,\" the officer added. Two men riding motorbikes hurled three bombs into a large beer garden, fired some shots and sped away after the shock attack Sunday evening, security sources told AFP by telephone from Maiduguri, capital of northeastern Borno state. \"The attackers, believed to be Boko Haram members, threw bombs and fired indiscriminate gun shots on a packed tavern at Dala Kabompi neighbourhood, killing at least 25 people and seriously injuring around 30 others,\" a police superintendent said. Emmanuel Okon, who sells charcoal-grilled beef on the fringes of the tavern, said: \"I just heard a loud bang followed by sporadic shootings and plumes of black smoke filled the area with people screaming and running in all directions. \"The wounded and the dead lay on the ground and the place was littered with broken bottles and glasses and... shoes,\" he said. When asked for further details on the attack, Mohammed Jinjiri Abubakar, the police commissioner for Borno state, declined to elaborate, saying that control for security had passed to the new task force. The force -- modelled on ones operating in the southern oil region of the Niger Delta and the sectarian clashes prone central city of Jos -- is taked with combatting the wave of bomb attacks and shootings blamed on the sect members. Boko Haram, which staged a short-lived uprising in 2009, has been blamed for what have become almost daily attacks and had hitherto targeted mainly police and military personnel, politicians and community and religious leaders. It has in recent months also bombed police stations, churches and staged a prison raid. The group claimed responsibility for the attack 10 days ago on police headquarters in the Nigerian capital Abuja that killed at least two, including a policeman, saying their target was the national police chief. The sect also said it was behind an attack on a beer garden in a military barracks in northern Bauchi city that killed over a dozen people hours after the inauguration of President Goodluck Jonathan. Boko Haram, whose name means \"Western education is a sin\", launched an uprising in 2009 which was put down by a brutal military assault that left hundreds dead, most of them its members.