"We support the resolution, although we do not feel that it is strong enough," Mahjub Husain, a spokesman for the Sudan Liberation Movement (SLM) said on Wednesday.
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," he said.
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.
A British report estimates that
300,000 people may have died
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.
A British parliamentary report released on Wednesday said as many as 300,000 people might have died in Darfur.
The report also urged the United Nations Security Council to
impose sanctions on Sudan, extend its arms embargo and refer war criminals to the International Criminal Court (ICC).
"The world's failure to protect the people of Darfur from the atrocities committed against them by their own government is a scandal," said Tony Baldry, chairman of the cross-party International Development Committee.
"The world's failure to protect the people of Darfur from the atrocities committed against them by their own government is a scandal"
Tony Baldry, International Development Committee chief
The committee said it believed about 300,000 people might have died, far higher than previous tolls which it said had underestimated the scale of the disaster.
It said it based its figure on estimates from UN Emergency Relief Coordinator Jan Egeland, who has said he believes the toll was much greater than a previous World Health Organisation estimate.
The UN health body estimated that 70,000 people had died
from hunger and disease in Darfur between March and October 2004, but with hard figures difficult to get, the toll has been fiercely contested.