The International Criminal Court has charged Sudan's president with masterminding a campaign of genocide in Darfur that has resulted in the deaths of 35,000 people and the persecution of 2.5 million refugees.
However, Sudan says it will ignore the move.
Prosecutor Luis Moreno-Ocampo asked the court on Monday for an arrest warrant for President Omar Hassan al-Bashir.
Mr Bashir is the first sitting head of state to be charged by an international court since Liberia's Charles Taylor and Yugoslavia's Slobodan Milosevic. The court was set up in 2002.
Thousands of demonstrators rallied in the capital Khartoum to protest at the move.
The central government in Khartoum is not a party to the court and denies genocide in Darfur. The government said it would ignore the announcement.
Mr Bashir said on Monday that the court had no jurisdiction in Sudan, adding that the charges were lies.
Mr Moreno-Ocampo said Mr Bashir masterminded a plan to destroy the Fur, Masalit and Zaghawa ethnic groups in Darfur who launched a rebellion in 2003.
He charged Mr Bashir with three counts of genocide, five of crimes against humanity, including murder, extermination, forcible transfer, torture and rape, and two of war crimes.
International experts say at least 200,000 people have died in Darfur and 2.5 million have been displaced since 2003. Khartoum says 10,000 people have been killed.
The African Union has warned that any attempt to arrest Mr Bashir would create a power vacuum in Sudan. Speaking on behalf of the union, Tanzanian Foreign Minister Bernard Membe said there would be an increase in anarchy and a risk of military coups.
Foreign ministers of the Arab League will hold an emergency meeting at the weekend to discuss the issue.
The United States called for more peacekeepers to be deployed to Darfur.
The United Nations has begun to withdraw non-essential staff from Darfur. It said staff were finding it increasingly difficult to operate in the region because of the deteriorating security situation.