Omar al-Bashir has been attending the Libya summit
The African Union says it will halt co-operation with the International Criminal Court over its decision to charge Sudan's leader with war crimes.
President Omar al-Bashir was indicted over alleged atrocities in the Darfur region in March.
But delegates to an AU meeting in Libya agreed a resolution saying they would not co-operate in his arrest.
Analysts say the move means the Sudanese leader can travel across the continent without fear of arrest.
The Sudanese government has been fighting rebels in Darfur since 2003.
The ICC has accused President Bashir of two counts of war crimes - intentionally directing attacks on civilians and pillage - as well as five counts of crimes against humanity, including murder, rape and torture, related to the conflict.
He denies the allegations, saying the state has a responsibility to fight rebels.
In a statement, the AU pointed out that its request to the ICC to defer Mr Bashir's indictment had been ignored.
It went on: "The AU member states shall not co-operate... relating to immunities for the arrest and surrender of Sudanese President Omar al-Bashir to the ICC."
The statement was backed by many African leaders who, analysts say, see the ICC as an attempt by the West to interfere in their affairs.
Sudanese Minister of State for Foreign Affairs Alsamani al-Wasila welcomed the move, describing the resolution as "very clear".
But, says BBC Africa analyst Martin Plaut, despite the Sudanese satisfaction a number of countries, including Chad and Benin, are reported to have expressed disquiet about the text.
It is also limited in scope, our analyst adds.
It does not ask the 30 African states that have signed up to the ICC to end their relationship with it.
Indeed, on the day this resolution was being passed, Kenya agreed explicitly to continue co-operating with the ICC, to prosecute those suspected of taking part in the violence that followed the December 2007 election.
The African Union decision is a blow to the court, but by no means a fatal one, our analyst says.
In a separate development, two female aid workers have been kidnapped in Darfur, reports say.
The pair - from Uganda and Ireland - were both working for the Irish charity Goal. They were seized from their compound in Kutum in northern Darfur by unidentified men, officials said.
It is the third time foreign aid workers have been kidnapped in Darfur since March.
The UN says 300,000 people have died and more than two million fled their homes since fighting erupted in 2003 between black-African rebel groups and the Khartoum government.