Maiduguri - Six people were killed on Friday when a suicide bomber blew himself up at a mosque in Damboa, northeast Nigeria, the army said, in the latest violence to hit the restive region.Nigerian Army spokesperson Colonel Sani Usman said the attack happened at about 05:15 in the town of Damboa, some 90km south-west of the Borno state capital, Maiduguri.He blamed the attack on "two Boko Haram terrorists"."The first suicide bomber targeted Damboa Central Mosque but due to stringent security measures, he could not gain entry. Obviously frustrated, he exploded [his device] and died near the central mosque," he added."However, the second bomber veered off and gained entry into another smaller mosque and detonated the bomb, killing himself and six other worshippers and injuring one other person."The wounded have been evacuated to a hospital while efforts are on to clear the rubble. Troops and other security agencies have been mobilised to the area."The attack is the latest against a mosque in northeast Nigeria and the wider Lake Chad region, as part of a campaign of violence by the Islamist group against civilian "soft" targets.On June 27, two would-be suicide bombers were killed in Maiduguri, as they tried to target an overnight Ramadan vigil at a mosque on the Damboa Road.Three days later, at least 10 people were killed in the town of Djakana, in northern Cameroon near the Nigerian border, when a suicide bomber blew himself up.On July 4, the Nigerian Army said it thwarted an attempted suicide bombing by three women against people displaced by Boko Haram in Monguno, northeast of Maiduguri.There has been a relative lull in attacks, as troops regain control of territory once held by Boko Haram, whose fighters have been pushed into remote rural areas towards Lake Chad.Usman said suspected Boko Haram fighters also attacked the village of Gaskeri, near the sprawling internally displaced people's camp at Dalori, outside Maiduguri, on Thursday night."They killed three civilian vigilantes and looted foodstuffs. Troops have been mobilised and they are on the suspected terrorists' trail," he added.The seven-year insurgency has left at least 20 000 people dead in Nigeria and displaced more than 2.6 million people, heaping pressure on local authorities in Nigeria, Niger, Cameroon and Chad.Aid agencies have warned that some 50 000 children under five are facing severe acute malnutrition in Borno alone this year because of food shortages caused by the conflict.UN assistant secretary-general and regional humanitarian coordinator Toby Lanzer said in a statement that "time is running out for the poorest and most rural of people" in the northeast."A failure to act now will result in deeper and broader suffering, unlike anything seen to date in Nigeria's northeast and a steeper bill for all concerned to alleviate suffering and stabilise the situation," he added.