Violence and human rights violations in Burundi are showing signs of worsening, top UN officials warned Monday, noting that the crisis could escalate into an atrocity, with the targeting of people based on political views and ethnicity, according to dpa. Top UN officials briefed an emergency session of the UN Security Council on the escalating situation in Burundi after recent reports of an increase in the killing of civilians belonging to the opposition. UN human rights chief Zeid Ra'ad al-Hussein called on the council to consider sanctions and other actions to put pressure on Burundian President Pierre Nkurunziza to stop the killing and arbitrary detention of protesters. "I appeal to you to keep Burundi at the top of your agenda and to explore all possible options to prevent further violence, including steps to freeze the assets of those who incite or engage in violence and possible travel bans," al-Hussein told the council. Adama Dieng, UN special advisor for the prevention of genocide, warned that the country was on the verge of violence that could "escalate into atrocity crime," noting that the situation was beginning to resemble that of Rwanda before the 1994 genocide. He noted that a recent speech by the president of the Burundian Senate used inflammatory language that "was very similar to the language used before and during the genocide of the Tutsis in Rwanda." "This speech adds to the fear that ruling party officials may be preparing the ground for widespread violence in Burundi," Dieng said. UN Secretary General Ban Ki-Moon called for an immediate end to violence in Burundi urging the country's security forces "to exercise maximum restraint." Ban also condemned that killing of at least seven people including a UN staffer in a bar on Saturday in the capital Bujumbura. He noted that preliminary reports showed that the attack was carried out by people in police uniforms. Meanwhile, at least six people were killed Monday as police searched pro-opposition neighbourhoods in Bujumbura for weapons. Five people were shot dead by police in the Musaga and Ngagara neighbourhoods of Bujumbura, said Pacifique Nininahazwe, leader of the Forum for Awareness and Development. Some of them were shot while fleeing in disobedience of orders from police to stop, Nininahazwe said. A police source who did not want to be named said one police officer was killed and two seriously injured when a grenade was hurled at them in Musaga. Nkurunziza had given civilians until Saturday to hand in illegal weapons. Hundreds of police and soldiers were carrying out door-to-door searches in Bujumbura, residents said. The United States remained "concerned about the potential for additional violence in Burundi connected with recent inflammatory rhetoric," State Department spokesman John Kirby said. Over the weekend, Secretary of State John Kerry telephoned with African Union Chairwoman Dlamini Zuma in support of regional efforts to resolve the crisis, and has sent special envoy Thomas Perriello to press for dialogue. "The United States calls on both government and non-government actors to refrain from violence," Kirby said. "We continue to stress the urgency for leaders in Burundi and across the East African community to call for calm and support the immediate convening of an inclusive, internationally mediated dialogue to resolve the current crisis." Al-Hussein said that at least 240 people have died during protests and attacks since April, when Nkurunziza announced his intention to seek a third term in office despite a two-term limit set by the constitution. The president then went on to win a July election boycotted by the opposition. "The [weapons] search is targeting those critical of the third term for the president," Nininahazwe said. More than 200,000 people have fled the violence to neighbouring countries.