The U.N. peacekeeping chief is calling on the government of Sudan to cooperate with the international chemical weapons watchdog in any investigation of alleged chemical weapons use in the Darfur region.

Herve Ladsous told the U.N. Security Council Tuesday that peacekeepers from the U.N.-African Union force in Darfur have been denied access to the area in Jebel Marra where Amnesty International alleged that at least 30 chemical attacks have taken place since January.

Ladsous told reporters: "We were very much alarmed by the allegations."

Sudan is a party to the Chemical Weapons Convention banning the use of toxic chemicals.

Sudan's U.N. Mission called the allegations "baseless" and denied that the country possesses chemical weapons. It said the Organization for the Prohibition of Chemical Weapons can visit its industrial facilities any time.