In a report released Tuesday, the panel said the UN-approved deliveries of military equipment to CAR's defense forces had "led to waves of rearmament" by some factions of the former Muslim Seleka alliance.

The rebel factions "believe that the government is preparing for a war against them", said the report sent to the Security Council last week.

In December, the council approved Russia's request to send light arms to build up CAR's armed forces which are being trained by the European Union as part of an effort to restore stability to the country.

Nine aircraft landed in Bangui in late January and early February to deliver the Russian weapons and ammunition, which are being gradually distributed to trained forces in the capital and beyond.

The Central African Republic exploded into violence following the 2013 overthrow of longtime leader Francois Bozize, prompting France to intervene with its Operation Sangaris.

The UN peacekeeping mission known as MINUSCA was deployed in 2014, but the country remains overrun with militias, many of whom claim to protect Christian or Muslim communities.

"The recent acquisition of weaponry by the government has created an incentive for the active rearmament of ex-Seleka factions," said the report, which reported a "hardening of the positions" of those groups.

"Armed group elements told the panel that, since the government had opted for the military option (training, rearming and attacking) instead of the political process, armed groups needed to be prepared."

- Arms deals in Sudan -

After Sudan moved to disarm rebels in Darfur, Seleka warlord Abdoulaye Hissene "reactivated his connections with Sudanese individuals eager to sell their weapons," said the report which covers the January to July period.

Since January, there has been a growing number of reports of arms-trafficking with former Seleka fighters "increasingly seen carrying pistols and AK-type assault rifles" in CAR's far-flung provinces.

The panel received information in April that the rebels had obtained Sudanese weapons including AK-type assault rifles, machine guns and ammunition and that "new weapons deals were being concluded" with the Sudanese traffickers.

Sudan's government said in a statement released by its embassy in Bangui in May that "the presence of mercenaries of Sudanese nationality within the ranks of armed groups has nothing to do with the Sudanese government."

After initially resisting the government's appeals for military aid, the council agreed to grant exemptions to an arms embargo to allow Bangui to build up its army and defense forces.

In June, CAR's defense minister asked a UN sanctions committee to allow deliveries of Chinese weapons for its national forces, but France, Britain and the United States put a hold on that request, citing concerns over the proposed shipment of anti-aircraft weaponry.

Despite the train-and-equip effort, the army, known as the FACA, "currently has insufficient capacity" to carry out operations "without the substantive and constant support of MINUSCA and/or the Russian instructors," said the report.

The panel noted that an African Union initiative for peace talks in CAR "has achieved some traction" and that a Russian national appointed as President Faustin-Archange Touadera's security adviser had met with rebel leaders.

It warned that a lack of coordination with the African Union peace drive "could be counterproductive, as it sends mixed messages to the armed groups."