DAKAR, Senegal — Thousands of people took to the streets of Sudan’s tense capital on Sunday in a carefully choreographed protest against the expected request by the International Criminal Court to arrest President Omar Hassan al-Bashir on war crimes charges.

Students and members of the ruling National Congress Party were bused to the center of the capital, Khartoum, where they waved banners denouncing the international court and the United Nations.

Sudanese officials said cabinet ministers held an emergency meeting to discuss how to respond to the request, expected on Monday, for the arrest of Mr. Bashir, who has ruled Sudan since taking power in a military coup nearly 20 years ago.

Sudan’s state-run television station broadcast a statement from the National Congress Party saying that the court’s actions would cause “more violence and blood” in Darfur, The Associated Press reported.

The chief prosecutor of the International Criminal Court, Luis Moreno-Ocampo, plans to ask that an arrest warrant be issued for Mr. Bashir, according to United Nations officials who have been briefed on his plans.

There is rising alarm in diplomatic circles, though, that charges against Mr. Bashir could jeopardize the vast aid and peacekeeping efforts in Darfur and undermine attempts to find a political settlement to end the crisis.

After being briefed on the prosecutor’s case on Friday, the African Union’s Peace and Security Council issued a statement expressing its “strong conviction that the search for justice should be pursued in a way that does not impede or jeopardize efforts aimed at promoting lasting peace,” and “reiterated the A.U.’s concern with the misuse of indictments against African leaders.”

Andrew S. Natsios, the former United States envoy to Sudan, bluntly condemned the prosecutor’s plans on the blog Making Sense of Darfur, which is published by the Social Science Research Council.

“Without a political settlement, Sudan may go the way of Somalia, pre-genocide Rwanda or the Democratic Republic of the Congo: a real potential for widespread atrocities and bloodshed as those in power seek to keep it at any cost because of the alternatives,” he wrote. “This indictment may well shut off the last remaining hope for a peaceful settlement for the country.”

Khartoum was relatively calm on Sunday despite the protests, which were tightly scripted and not violent. Embassies and aid organizations urged their workers to stock up on food and water, and some evacuated workers from Darfur.

United Nations officials struggled to find ways to protect the roughly 9,000 peacekeeping troops in the Darfur region. Originally sent to protect civilians from the cataclysmic violence — 300,000 people have died, according to the United Nations, and 2.5 million have fled their homes — the peacekeepers have found themselves increasingly in the crosshairs of the rising chaos in the region.

“People are afraid,” a senior peacekeeping official in Darfur said in a telephone interview. “Anything can happen.”

Ban Ki-moon, secretary general of the United Nations, called Mr. Bashir on Saturday to express concern about the safety of United Nations personnel in Sudan and to stress that the work of the court was independent from the rest of the United Nations, his office said in a statement.

The secretary general also said he was “gravely concerned about the scale and brutality” of a brazen attack on a convoy of peacekeepers returning from a patrol to investigate reports of atrocities committed by a government-allied rebel group in Darfur.

The attack, which left seven peacekeepers dead, was unusual in its coordination and sophistication, according to peacekeeping officials, involving heavy weapons and tactics that require serious military training. That has led some officials to suspect that Sudanese government-trained militias were behind the ambush.

Ali al-Sadig, a government spokesman, said Sudan’s government condemned the attack, adding that evidence investigators had gathered pointed to one of the rebel factions in Darfur.

The peacekeeping force in Darfur, a joint operation of the United Nations and the African Union, could be a prime target of violence and government anger after the announcement by Mr. Moreno-Ocampo, the prosecutor. Already strained by the deteriorating security in Darfur, the force could collapse, United Nations officials said.

“We are a consent-based organization, and if consent is withdrawn, you are looking at a radically different and terrifying situation for the people on the ground,” said one official at the Department of Peacekeeping Operations in New York, speaking anonymously because he was not authorized to speak publicly.

Anti-genocide and human rights advocates have cheered the decision to request charges against Mr. Bashir, calling it a victory in the battle against impunity. They point out that similar objections, that war crimes charges would hinder peace, were raised in other such cases, including when international courts charged leaders with committing war crimes in Sierra Leone and the former Yugoslavia.

Hussein Abu Shartai, a spokesman for displaced Darfurians living in Kalma, one of the region’s largest and most volatile camps, praised the prosecutor, calling the request for an arrest warrant “the moment we have all been waiting for.”

There were intense consultations at the United Nations on Friday among Security Council members, including Russia and China, which oppose the indictment, and others, including the United States, that say the indictment should be allowed to proceed.

The Sudanese ambassador, Abdalmahmood Abdalhaleem Mohamad, said Friday that Sudan would ignore any court action because it was not a member of the court.

“It is a criminal and destabilizing move,” he said. “How is the U.N. going to deal with an indicted president?”