KHARTOUM, Sudan - Sudan's president, wanted by an international court on war crimes charges, denounced the tribunal, the UN and aid agencies on Thursday as part of a new "colonialism" that aims to destabilize his country.

President Omar al-Bashir danced and waved a cane defiantly before thousands of supporters, as the arrest warrant had its first repercussions on the ground.

Sudan ordered at least 11 aid agencies to leave Darfur and cease operations in retaliation for the International Criminal Court's decision to issue an arrest warrant. The groups started the process of moving out on Thursday.

Aid workers warned that the expulsion order could spark a humanitarian crisis for up to two million people in Darfur who are directly served by the agencies, receiving food, shelter and medical supplies.

In Zamzam Camp, one of the largest Darfur refugee camps, residents said aid workers who operate daily in the camps did not show up on Thursday.

Refugees said they now feared what will happen when their most recent monthly delivery of food and other supplies run out, if aid workers don't return. Particularly worrisome is the pullout of health workers, and the possibility of disease outbreaks in the upcoming rainy season.

"After God, we only have the organizations" to help us, said Zamzam camp resident Ibrahim Safi, 34. He called the expulsion order a "catastrophe."

Speaking for the first time since the warrant was issued Wednesday, al-Bashir told a cabinet meeting that those agencies, the UN and the tribunal are "tools of the new colonialism" meant to bring Sudan and its resources under control.

Al-Bashir accused the aid organizations of trying to disrupt peace efforts in Darfur, profiting from the conflict and interfering with foreign investment. He said his government ordered them out of Darfur because they violated the law.

"We in Sudan have always been a target of the UN and these organizations because we have said, `No'," al-Bashir said. "We said the resources of Sudan should go to the people of Sudan."

Hasabo Abdel-Rahman, the head of the government agency co-ordinating humanitarian affairs, also accused the aid groups of co-operating with the ICC and offering the court "false" testimonies.

At least 2.7 million people in the large, arid region of western Sudan have been driven from their homes, most to camps in Darfur and neighbouring Chad, in the war between Darfur rebels and the government since 2003. Even many who remain in their homes depend on international aid to survive.

UN Secretary General Ban Ki-moon called Sudan's order "a serious setback to life-saving operations in Darfur." The aid groups, which included Oxfam, CARE and Save the Children, protested that they had nothing to do with the Netherlands-based ICC's decision.

Medecins Sans Frontieres, also known as Doctors Without Borders, said its French branch was ordered expelled -- a day after its Dutch section received the order to stop operating in Darfur.

UN agencies were expected to continue working in Darfur. But it was unclear how the expulsion orders would affect supply distribution, since much of the UN humanitarian supplies are given to aid agencies to deliver.

"The impact is going to be huge. We were assisting 600,000 people in parts in Darfur with lifesaving activities like water and food distribution," said Bea Spadacini, a Kenya-based spokeswoman for CARE.

She said CARE's 650 employees in Sudan, a majority of whom are Sudanese, stopped working Wednesday after the government revoked its licence.

In the capital, Khartoum, senior UN officials were meeting with government officials, trying to negotiate a deal to stay.

Al-Bashir, who faces charges of war crimes and crimes against humanity, is accused by the ICC of overseeing an anti-insurgency campaign in Darfur in which atrocities were carried out against civilians. At least 300,000 people have died in Darfur in the fighting, which pits ethnic African rebels against the Arab-led Khartoum government and Arab militiamen.

Appearing before tens of thousands of supporters at a Khartoum rally Thursday after the cabinet meeting, al-Bashir warned international missions and organizations still operating the country "to respect themselves," saying they would be "humiliated" if they infringe on Sudan's sovereignty.

Al-Bashir danced with the cheering crowd outside his Republican Palace in the biggest demonstration in Sudan in years. "We are ready to resist colonialism," he said, jabbing his cane in the air as he spoke. "We are ready to defend our religion."

The arrest warrant is the ICC's first against a sitting head of state. Al-Bashir has rejected the charges and his government has said it will not co-operate with the court. UN officials said their staff will continue to deal with al-Bashir in Sudan because he remains the president of the country.

International groups might have drawn the president's ire in part by repeatedly criticizing China, which buys two-thirds of Sudan's petroleum exports, for not using its economic leverage to apply more pressure on al-Bashir's government.

China's Foreign Ministry spokesman Qin Gang told a news conference Thursday that China backs a call by the African Union and Arab countries to have any prosecution of al-Bashir deferred.