The U.N. Security Council on Monday strongly condemned violations of human rights and international humanitarian law in the Central African Republic and warned that attacks on United Nations peacekeepers there may constitute war crimes.

The press statement was issued after closed-door Security Council discussions and a briefing from Mankeur Ndiaye, the U.N. special envoy to the Central African Republic. Earlier, the council held an open meeting on the broader central Africa region where the United States and Russia traded accusations over actions in the Central African Republic.

U.S. political coordinator Rodney Hunter expressed outrage at reports that Russian military instructors led military offensives in the country “characterized by confrontations with U.N. peacekeepers, threats against U.N. personnel, violations of international humanitarian law, extensive sexual violence, and widespread looting, including of humanitarian organizations.”

Russia’s deputy U.N. ambassador, Anna Evstigneeva, accused the U.S. of making “baseless allegations” and said the U.S. action, coupled with a campaign in some media, “constitutes a coordinated action aimed at besmirching our effective … assistance to stabilization in the CAR.”

She said cases of suspected violations of international humanitarian law should be investigated by competent bodies in the country once they receive “meaningful evidence and facts,” and she called U.S. threats to revoke bilateral assistance to nations in difficult positions “blackmail.”

The sessions followed a May 30 border incident that has heightened tensions between the Central African Republic and Chad.

Chad’s defense ministry said troops from the neighboring country attacked a Chadian border post, killing one soldier and kidnapping and then executing five others. Russia’s RIA Novosti news agency reported three Russian military instructors, part of a mission to support the Central African Republic’s military, were also killed during the operation by a mine explosion.

The agency quoted Russian deputy foreign minister Mikhail Bogdanov as saying Wednesday that the deaths would not lead Russia to decrease the number of military instructors, who are there at the invitation of the Central African Republic government.

The Security Council statement issued after its closed meeting gave no details of the reported human rights and humanitarian violations.

It urged the Central African Republic to ensure that it complies with the status of forces agreement with the United Nations, which has a 15,000-strong peacekeeping force in the country.

Council members called on the country’s authorities, U.N. peacekeepers “and all forces present on the ground to coordinate and take all appropriate measures to enhance the safety and security of United Nations peacekeepers and personnel.“

The mineral-rich Central African Republic has faced deadly inter-religious and inter-communal fighting since 2013. A peace deal between the government and 14 rebel groups was signed in February 2019, but violence blamed on the country’s former president, Francois Bozize, and his allies threatens to nullify the agreement. It erupted after the constitutional court rejected Bozize’s candidacy to run for president in December.

President Faustin Archange Touadera won re-election in late December to a second term with 53% of the vote, but he continues to face opposition from forces linked to Bozize.

The Global Center for the Responsibility to Protect reported on May 31 that “armed groups continue to control the majority of territory in CAR and profit from illegal taxation and arms trafficking, and the cross-border flow of foreign fighters, arms and natural resources are fueling the crisis.”

“A climate of impunity has enabled ongoing violence and allegations of serious human rights violations and abuses by armed groups as well as state security forces and their allies,” said the report by the center, which was established in 2008 by governments, non-governmental groups and leading human rights figures including the late former U.N. Secretary-General Kofi Annan.