"We support the resolution, although we do not feel that it is strong enough," Mahjub Hussein, a spokesman for the Sudan Liberation Movement (SLM) told AFP.
He added that his group had hoped for a resolution imposing additional sanctions on the government itself rather than individuals.
"We wanted tougher sanctions against the government," said Hussein.
The resolution approved on Tuesday allows for the seizure of assets and a travel ban against individuals who commit atrocities, impede the peace process in Darfur or "constitute a threat to stability" in the region.
Violators will be identified by a new committee that will include all 15 Security Council members.
The council approved the US-drafted resolution by 12 votes to zero with abstentions from Algeria, China and Russia -- and amid fierce opposition from the Sudanese government in Khartoum.
The resolution also extended an existing arms embargo against non-state parties in Darfur to the Sudanese government and specifically prohibited Khartoum from offensive military flights into the region.