KHARTOUM (AFP) -- The Sudanese government ordered the partial suspension of UN operations in Darfur late Saturday after the world body allegedly gave a helicopter ride to a rebel leader.

The Foreign Ministry said in a statement that the ban did not affect the work of the World Food Program (WFP) and the UN Children's fund (UNICEF), the two largest agencies to operate in the war-torn western Sudanese region. The ministry slapped on the ban "pending and explanation by the UN Secretary General's representative in the Sudan (Jan Pronk) about carrying a leader of an armed movement who works for undermining the Darfur peace agreement."

The statement did not name of the rebel leader but two main factions have so far refused to fully endorse the peace deal reached last month between Khartoum and Minni Minawi's faction of the Sudan Liberation Army/Movement.

The Foreign Ministry charged that the United Nations flew the unnamed rebel leader in one of its helicopters Saturday from Darfur's largest town of El-Fasher to the town of Kadugli in South Kordofan to the east.

"It was clear that the act was planned to take place behind the back of the Sudanese authorities," the statement said.

There was no immediate reaction from the United Nations. The Foreign Ministry said it considered the incident "a flagrant violation of the country's sovereignty and a violation of the agreement under which the UN operates in Sudan."

The United Nations is conducting the largest humanitarian operation in the world in Darfur, an area roughly the size of France where up to 300,000 people have been killed and 2.4 million displaced by three years of civil war.