UNITED NATIONS (AP) — Russia is holding up the appointment of independent experts to monitor implementation of sanctions on four African countries, saying the panels proposed by the U.N. secretary-general are not geographically balanced and some members are not impartial, U.N. diplomats said Wednesday.

The Russian refusal to sign off on members of new expert panels is already delaying investigations of sanctions violations in South Sudan, Congo and Central African Republic, said the diplomats, insisting on speaking anonymously to reveal details of what are supposed to be private consultations. The mandate for the panel of experts on Mali expires Thursday.

The U.N. Security Council has to approve new panels before the monitoring of sanctions can continue, and Russia has veto power in the U.N.'s most powerful body.

Russia's deputy U.N. ambassador, Dmitry Polyansky, told The Associated Press late Wednesday: “We can’t approve unbalanced composition of the sanction committees. And this issue unfortunately hasn’t been duly taken care of by the U.N. Secretariat. So we hope a solution will be found soon."

There was no immediate response to an email to Secretary-General Antonio Guterres’ spokesman seeking comment.

In recent years, Russia has become much more active in Africa, especially the Central African Republic and Mali.

In late June, U.N. experts accused Russian military instructors and the Central African Republic forces they are supporting of “excessive use of force, indiscriminate killings, the occupation of schools and looting on a large scale.” Moscow strongly denied the allegations.

Last September, experts monitoring sanctions in Libya said the warring parties and their international backers — the United Arab Emirates, Russia and Jordan vs. Turkey and Qatar — violated a U.N. arms embargo on the oil-rich north African country that remains “totally ineffective.”

Their report also said 11 companies violated the arms embargo, including the Wagner Group, a private Russian security company. In May, the panel said Wagner provided between 800 and 1,200 mercenaries to support eastern Libya’s rebel commander Khalifa Hifter.

The mandate for the Libya panel of experts doesn’t expire until Aug. 15, 2022.