UNITED NATIONS — Amnesty International is calling on the U.N. Security Council to take action over reports that the Sudanese government has used chemical weapons in Darfur.

The British-based human rights group released a report Thursday detailing at least 30 chemical attacks they say took place in the Jebel Marra area over the past eight months. Amnesty estimates that chemical weapons may have killed some 200 to 250 people, with many or most being children.

“The world cannot stand idly by any longer. The U.N. needs to act. A cloud of suspicion hangs over the Sudanese authorities’ conduct in Darfur,” said Tirana Hassan, adding the alleged attacks have “every sign of being a war crime.”

U.N. spokesman Stephane Dujarric said the world body is “extremely and particularly concerned” by the report.

He pointed out, however, that the Sudanese government has consistently denied the U.N. peacekeeping mission there access to conflict areas in Jebel Marra, so there was no way to ascertain the veracity of the report.

“In terms of chemical weapons, Sudan is a party to the chemical weapons convention. Any allegations of violations of that convention will be examined by the OPCW,” Dujarric said, referring to the Organization for the Prohibition of Chemical Weapons. He said the OPCW was aware of the report.

Sudan’s U.N. Ambassador Omer Dahab Fadl Mohamed responded in a statement calling the Amnesty report “baseless and fabricated” and denying that his country had any chemical weapons.

Darfur has been witness to bloodshed since 2003, when rebels took up arms against the government in Khartoum, accusing it of discrimination and neglect. The U.N. estimates 300,000 people have died in the conflict and 2.7 million have fled their homes.

A recent United Nations report found that the Sudanese government continues to violate sanctions imposed by the Security Council over their actions in Darfur.

The report outlined violations of the arms embargo, the use of cluster bombs by the Sudanese government and the illegal transfer of intrusion software with electronic intelligence capability among other things. It also documented numerous human rights violations attributable to the government and the financing of armed groups within the country which act as proxy forces.

Sudan’s leader, Omar al-Bashir, is wanted by the International Criminal Court for alleged atrocities in Darfur. The court issued an arrest warrant for al-Bashir in 2009 for crimes against humanity and war crimes and added genocide to the charges against him in 2010.