Abuja - The Nigerian government on Monday said up to 150 people had been killed by Boko Haram in the country's north last week and dismissed widespread reports that 2 000 people had died."Without any doubt, terrible atrocities have been committed against innocent Nigerians in Baga by the rampaging terrorists," the defence ministry said in a statement.But the higher death tolls being reported were the result of "speculations and conjectures ... peddled by a section of the press", the ministry said.The figure of 150 dead, determined from surveillance and investigation, included many dead terrorists, it said.Local officials have reported since Thursday that the militant Sunni Islamist group had attacked and razed more than a dozen villages in the region. Thousands of people have fled the region into Chad, according to the United Nations.Worst terrorist actionAmnesty International has described the attacks as the worst terrorist action in Nigeria.The Nigerian government has typically been restrained in its comments on the attacks. In the past, it has typically tried to downplay the number of dead from attacks by Boko Haram.The Nigerian-based group is exercising a reign of terror across northern Nigeria, Chad and Cameroon, and has killed thousands of people in its push to create an Islamist state in Nigeria.Among the missing are more than 200 girls abducted from a school earlier this year.On Saturday, a 10-year-old girl detonated herself in a suicide bombing at a north-eastern Nigerian market, killing 20 and injuring 18, a local newspaper reported.On Monday, Cameroonian troops killed at least 33 Boko Haram militants, an army spokesperson said. The insurgents attacked a military base in Kolofata in the north, Didier Badjeck told dpa.