The African Union summit in Ethiopia has agreed to a resolution stating that no African head of state should appear before an international court.
It demanded a deferral of The Hague trial of Kenyan President Uhuru Kenyatta, due to start in November.
With both Kenyan and Sudanese presidents facing ICC cases, African leaders have long complained that the court unfairly targets them. The AU had discussed withdrawing from the ICC, but failed to get support. Senior figures including Kofi Annan have criticised plans to quit the ICC.
The AU leaders, meeting in Addis Ababa, agreed to back immunity for any sitting African head of state.
They also asked Kenya to write to the UN Security Council seeking a deferral in the International Criminal Court (ICC) cases against Kenyan President Uhuru Kenyatta and his deputy, William Ruto.
Ethiopian Prime Minister Hailemariam Dessalegn said the summit was not a crusade against the ICC but a call for the court to address Africa’s concerns seriously.
He said the ICC’s cases against the Sudanese and Kenyan presidents could hamper peace and reconciliation efforts in their countries.
“The unfair treatment that we have been subjected to by the ICC is completely unacceptable,” he said.
Both Kenyan leaders deny charges of organising violence after the 2007 election.
The ICC issued a warrant in 2009 for Sudanese President Omar al-Bashir over alleged war crimes in the Darfur region, but he has not yet been arrested.
The ICC relies on the authorities of national governments to hand over suspects, but Mr Bashir has avoided arrest despite travelling to countries that have signed up to the ICC statute.