Attacks by Islamist group Boko Haram in Nigeria's restive northeast have killed more than 1,200 people since May, when a state of emergency was declared in the region, the United Nations said Monday.
Nigeria placed the states of Adamawa, Borno and Yobe under emergency rule on May 14, following waves of deadly violence by the Islamist rebels.
President Goodluck Jonathan sent thousands of troops backed by air support to the northeast to crush the four-year-old uprising.
The UN toll is the first independent fatality figure to have emerged since the military operation was launched.
"Some 1,224 people have been killed in Boko Haram related attacks" since May, the UN humanitarian agency (OCHA) said in a statement.
The toll includes civilians, military personnel as well insurgents killed by security forces repelling attacks.
But OCHA spokeswoman Choice Okoro told AFP that UN figure did not include insurgents killed during targeted military operations.
Defence officials have in recent months released a series of statements claiming scores of rebel deaths in operations on Boko Haram strongholds.
The details of those statements have been difficult to verify amid a communication blackout in much of the northeast and the military has been widely accused of downplaying fatalities among civilians and its own personnel.
"The humanitarian situation in northeast Nigeria has been increasingly worrisome over the course of 2013," the UN said, adding that there have been 48 separate "Boko Haram related" attacks in the region since emergency rule was declared.
Among the most gruesome was a pre-dawn massacre at an agricultural college in Yobe state, during which gunmen entered dormitories under the cover of darkness and shot dead 40 students in their sleep.
OCHA noted that "information on the situation is scarce," with figures of those displaced by the conflict and those who have fled to neighbouring states "hard to gauge."
The military had switched off the mobile network across the region, apparently to block Islamists from coordinating attacks.
Officially, mobile service has been restored in all three states, but communication remains difficult in Borno, the epicentre of the insurgency and where Boko Haram was founded more than a decade ago.
Jonathan, who has described the military offensive as a success, has extended the state of emergency through to May of next year, a move he said was necessary to clear out remaining Boko Haram strongholds.
While the security forces have not stopped the bloodshed, they have largely succeeded in containing Boko Haram in the northeast, the group's historic base.
Through 2012, the insurgents staged attacks across the wider north, including near-weekly suicide bombings at churches in major population centres.
Boko Haram, declared a terrorist organisation by the United States in November, has said it is fighting to create and Islamic state in Nigeria's mainly Muslim north.
Washington also slapped a $7 million (5.1 million euros) bounty on the group's purported leader, Abubakar Shekau, who has ruled out any form of negotiations with the government.