United Nations support for a planned military operation against Rwandan rebels in eastern Democratic Republic of Congo could be in doubt because Congo named a general accused of rights abuses to head the offensive, diplomats and officials said on Friday.

General Bruno Mandevu was appointed on Sunday to head a Congolese army (FARDC) operation against the Democratic Forces for the Liberation of Rwanda (FDLR), which had been jointly planned with the U.N. peacekeeping mission in Congo (MONUSCO).

Western diplomats, speaking on condition of anonymity, said Mandevu had been placed by MONUSCO on a so-called red list over accusations of 121 rights violations, including summary executions and rapes.

“If, because of the past record of units or their commanders, there are substantial grounds to believe there is a real risk that they commit grave human rights violations, support to those units will be withheld unless adequate mitigating measures can be put in place,” a senior MONUSCO official told Reuters.

“In this particular case, this process has brought to light some concerns that have been brought to the attention of the DRC government. Discussions are underway at the highest level to address them,” the official said.

During a U.N.-backed offensive against the FDLR in 2009, Congolese soldiers were accused by rights groups of massacring hundreds of civilians and committing wide-ranging abuses. The Congolese army denied the scale of the alleged abuses.

The FARDC and the Congolese government were not immediately available for comment.

A U.N. peacekeeping official in New York said that under the United Nations human rights due diligence policy, the world body has to “ensure that its support to non-U.N. security forces will not contribute to grave human rights violations.”