Plateau State , Nigeria ( CNN ) -- Gunmen attacked a mosque in Nigeria with automatic weapons over the weekend , killing at least 44 people , a local police official said . It 's not clear who was behind Sunday 's massacre , but the militant Islamist group Boko Haram -- which has staged attacks in the same region before -- issued a video around the same time boasting that it was gaining in strength . Details have been slow to emerge about the attack in Konduga , about 30 kilometers ( almost 19 miles ) southeast of Maiduguri , the capital of Nigeria 's northern Borno state . The police official in Konduga spoke to CNN on condition of anonymity because he is not authorized to speak to the media . Another 26 victims were brought into Maiduguri Teaching Hospital for treatment on Sunday , some in critical condition , a source at the hospital who asked not to be identified told CNN . Some villagers in Borno state have also been attacked in their own homes , accused of collaborating with government forces against Boko Haram , police sources said . Local media reported that at least 12 people were killed on Saturday night in Ngom village alone . Opinion : Nigeria 's peace 'the peace of a graveyard ' In the video released by Boko Haram , its leader Abubakar Shekau claimed that the militant group is growing stronger despite the Nigerian military 's efforts to curb its activities . `` You soldiers have claimed that you are powerful , and that you have defeated us , you say we are mad people ; but how can a mad man organize the attacks in Gamboru , in Malumfatori , slaughter people in Biu , kill in Gwoza and in Bama successfully , where soldiers fled under our heavy fire power ? '' he said . `` We have killed countless soldiers and we are going to kill more . Our strength and firepower is bigger than that of Nigeria . Nigeria is no longer a big deal to us , as far as we are concerned . `` We will now comfortably confront the United States of America . '' Shekau said the group would continue to kill unbelievers and `` anyone who stands against the will of Allah by opposing Sharia , '' or Islamic law . Boko Haram has often targeted Christians in Nigeria but the group will also attack other Muslims when it feels they are not adhering to strict Sharia law . There have been suggestions that the group has attacked certain mosques because worshippers at that mosque have assisted government forces in tracking members of the militant group . 'Contemptible act ' The U.S. State Department named Shekau as a `` specially designated global terrorist '' in June last year . This year , it offered up to $ 7 million for information leading to his arrest or conviction , under its Rewards for Justice Program . Britain and Spain each condemned the attack in Borno state and offered their condolences Tuesday to the victims and their families . `` This senseless attack has reportedly killed 44 people and left many others injured . Attacking innocent people in a place of worship is a contemptible and cowardly act , '' said Mark Simmonds , UK Foreign Office Minister for Africa . `` The UK stands with the government and people of Nigeria as they seek to reduce violence in the north east of the country . '' Spain 's Foreign Ministry `` called on the authorities to advance their efforts to arrest the offenders , probably part of the Boko Haram terrorist group , bring them to justice , and put an end to the activities of the group which threatens the peace and coexistence in the country . '' Gunmen kill 20 students , teacher in Nigerian school shooting . State of emergency . Boko Haram , whose name means `` Western education is forbidden , '' seeks to overthrow the Nigerian government and replace it with a regime based on Islamic law . A state of emergency has been imposed in Borno state since May 14 , including a complete communications blackout , as authorities seek to tackle the militant group . Yobe and Adamawa states , which border Borno state , were placed under a state of emergency at the same time . Declaring the state of emergency in May , Nigerian President Goodluck Jonathan blamed `` terrorists '' aimed at `` rebellion '' who have caused `` fear among our citizens and a near breakdown of law and order in parts of the country . '' He said the terrorists were mounting a `` rebellion and insurgency '' that threatened Nigeria 's unity and stability , and pledged to send more troops to the three northeastern states . `` We have taken robust steps to unravel and address the root causes of these crises , but it would appear that there is a systematic effort by insurgents and terrorists to destabilize the Nigerian state and test our collective resolve , '' he said in a televised speech . With an estimated 174.5 million people , Nigeria is Africa 's most populous nation . The CIA World Factbook says the nation is roughly 50 % Muslim and 40 % Christian . Violence between the mainly Muslim north and Christian south has taken at least 2,800 lives , according to Human Rights Watch . Opinion : How African innovation can take on the world . Journalist Hassan John reported from Nigeria and CNN 's Nima Elbagir from Nairobi , Kenya . CNN 's Laura Smith-Spark , Nick Thompson and Mohammed Tawfeeq contributed to this report .
NEW : 26 people were injured in the mosque attack in Borno state , a medical source says . At least 44 people died when gunmen attacked the mosque , a police official says . Villagers have also been attacked for helping the government , police sources say . Boko Haram leader released a video over the weekend , boasted of the group 's strength .