Nigerian security forces killed at least 23 people after a bomb blast blamed on Islamists over the weekend, allegedly randomly shooting and burning a market, Amnesty International said on Monday. The allegations were the latest against Nigerian security forces operating in the northeastern city of Maiduguri, which has been hit by scores of bomb blasts and gun attacks blamed on an Islamist sect known as Boko Haram. \"The Nigerian authorities must immediately put a stop to unlawful killings by security forces,\" the rights group said in a statement. \"...At least 23 people were killed by police following a bomb blast on Saturday in the northeastern city of Maiduguri.\" Amnesty said the Joint Military Task Force, assigned to Maiduguri to deal with the wave of attacks, responded to the bomb blast with heavy force. The military has said the blast wounded three soldiers. \"According to reports received by Amnesty International, the Nigerian Joint Military Task Force responded by shooting and killing a number of people, apparently at random, before burning down the market,\" it said. Residents of the neighbourhood had earlier made similar accusations against security forces in interviews with AFP. A military spokesman earlier dismissed the residents\' accusations as \"outright lies,\" insisting that no civilian casualties were recorded on Saturday. \"The fire that burnt homes, shops and vehicles was caused by the impact of the explosion of the bomb detonated by the Boko Haram attackers,\" said Lieutenant Colonel Hassan Isijeh Mohammed. It was not the first time troops were accused of abuses in Maiduguri. Amnesty has previously said that at least 25 people were killed during a military raid after another bomb blast in Maiduguri earlier this month and many others were reported missing. At the time, Amnesty said that \"reports say members of the security forces have repeatedly threatened to shoot everyone in the area if they fail to tip them off about future bombs.\" Residents reported then that soldiers accused them of cooperating with the Islamists. The military also denied those allegations, but elders from the area had afterward called for the troops to be withdrawn. The government has resisted calls to pull out the troops, saying the situation would only worsen. Thousands of people have already fled Maiduguri out of fears of further violence. The city has been extremely tense in recent weeks, with bomb blasts and shootings occurring almost daily. Saturday\'s blast shook an area near the palace of the Shehu of Borno, an influential traditional and religious leader, though it did not seem the palace was targeted. \"Soon after the bomb went off, military vehicles arrived and soldiers besieged the neighbourhood, shooting indiscriminately and setting houses and shops in and around the market on fire,\" one resident told AFP. \"They went about burning vehicles and in some cases along with the occupants.\" The sect claims to be fighting to establish an Islamic state in Nigeria, Africa\'s most populous country of some 150 million people, roughly divided between Christians and Muslims. But its source of financing and support remains unclear, and there has been widespread speculation over whether some of the attacks have been politically linked. It also remains unclear whether Boko Haram has links with Islamist groups outside of Nigeria -- an issue that has drawn the attention of Western nations. The sect launched an uprising in 2009 that was put down by a brutal military assault which left hundreds dead and destroyed the Islamists\' mosque and headquarters in Maiduguri.