Ethiopia's foreign minister opened a special African Union summit Friday with a scathing attack on the International Criminal Court, blasting what he said was its "unfair" and "totally unacceptable" treatment of Africa.

The special summit comes amid mounting tensions between The Hague-based court and Kenya, whose president and vice-president have been charged with committing crimes against humanity during election-related violence in 2007-2008.

Several nations in the 54-member AU, whose rotating presidency is currently held by Ethiopia, have accused the ICC of singling out Africans for prosecution, and have specifically demanded that the court drop the proceedings against Kenya's leadership.

"The manner in which the Court has been operating, particularly its unfair treatment of Africa and Africans, leaves much to be desired," Ethiopian Foreign Minister Tedros Adhanom Ghebreyesus told ministers and delegates at the opening of the two-day meeting.

"Far from promoting justice and reconciliation... the court has transformed itself into a political instrument. This unfair and unjust treatment is totally unacceptable," he said of the ICC, the world's first permanent court to try genocide, war crimes and crimes against humanity.

South African anti-apartheid icon and Nobel peace laureate Desmond Tutu on Friday fired off a sharply-worded attack that compared ICC opponents to Nazis seeking to evade justice, and argued the number of African cases was merely a reflection on the human rights situation on the continent.

"Those leaders seeking to skirt the court are effectively looking for a license to kill, maim and oppress their own people without consequence. They believe the interests of the people should not stand in the way of their ambitions of wealth and power," he wrote in an op-ed carried by several newspapers.

"They simply vilify the institution as racist and unjust, as Hermann Goering and his fellow Nazi defendants vilified the Nuremberg tribunals following World War II," he wrote.

Former UN secretary-general Kofi Annan has also said a pull-out would leave Africa wearing a "badge of shame", while a group of 130 African civil society and human rights organisations have also issued a public letter expressing their steadfast support for the tribunal.

The ICC has charged Kenyan President Uhuru Kenyatta and Vice-President William Ruto, as well as former radio boss Joshua Arap Sang, with crimes against humanity linked to post-election violence in 2007-2008 that left at least 1,100 dead and more than 600,000 homeless.

The trial of Ruto and Sang has already begun, and proceedings against Kenyatta are due to start on November 12. The accused are all cooperating with the court, but tensions have been mounting amid accusations of witness intimidation by the accused and counter-complaints against the ICC that it is inflexible.