Between 200 and 250 people including many children may have died as a result of exposure to chemical agents
The UN peacekeeping chief on Tuesday urged Sudan to help shed light on allegations of chemical weapons attacks in Darfur, but Russia said the claims must not be taken seriously.
In a report released last week, Amnesty International accused Sudanese government forces of carrying out more than 30 attacks this year using toxic agents in mountainous villages of the Jebel Marra region.
The Organization for the Prohibition of Chemical Weapons (OPCW) said in response that it would require further information and evidence to push ahead with a formal investigation.
Herve Ladsous, the UN under-secretary-general for peacekeeping, told the Security Council that he encourages Sudan "to maintain full cooperation with any future OPCW investigation, as it has expressed readiness to do so."
Sudan has signed the Chemical Weapons Convention, the international agreement outlawing the use of chemical weapons.
Amnesty said that between 200 and 250 people including many children may have died as a result of exposure to chemical agents during the attacks.
France and Britain have said the allegations should be thoroughly investigated, but Russian Ambassador Vitaly Churkin said the report was unconvincing.
"Those allegations are not serious. There are so many reasons to believe they are not serious," Churkin told reporters.
Khartoum has blocked peacekeepers from the joint UN-African Union mission in Darfur (UNAMID) from gaining access to Jebel Marra, where Ladsous said the situation remains "volatile."
Up to 194,000 people have been displaced in Jebel Marra since mid-January when the Sudanese army launched a military campaign against the rebel Sudan Liberation Army - Abdul Wahid (SLA/AW) group, the United Nations says.
Darfur has been engulfed in a conflict since 2003 when ethnic minority groups took up arms against President Omar al-Bashir's Arab-dominated government, which launched a brutal counter-insurgency.
At least 300,000 people have been killed and 2.5 million displaced, the United Nations says.