Last weekend in Haiti, at least 184 people were reported killed in an area called Site Soleil in the capital Port-au-Prince between December 6-8.
It is feared that some armed group may have done this incident. Among the dead, 127 were reported to be elderly men and women.
Stephane Dujarric, a spokesman for the top UN official, issued a statement on his behalf on Monday, expressing his deepest condolences to the victims and their families.
The Secretary-General appealed to the Haitian government to conduct a thorough investigation into the matter and hold all those responsible accountable. Those responsible for human rights abuses and violations must be brought to justice, he said.
Gang violence has killed more than 5,000 people so far this year, although the actual number is expected to be higher.
Seven million people in Haiti are internally displaced, of which nearly 50 percent are children. More than 5.5 million people are in need of humanitarian assistance.
Need help and support
Last month, UN Resident Coordinator Ulrika Richardson said that humanitarian resources in Haiti are limited and the burden is increasing as the situation worsens.
Secretary-General Guterres called on member states to provide adequate financial and operational support to the Kenya-led Multinational Security Assistance Mission to control the situation in Haiti.
According to him, this support is needed for the Haitian National Police to suppress the violence of criminal groups. At the same time, he appealed to all stakeholders in Haiti to move quickly to achieve progress towards political change.
The United Nations Security Council in September this year approved the deployment of the Multinational Security Assistance Mission to Haiti, a Caribbean country struggling with instability and violence, for 12 months.