N'djamena - Sudenese refugees urged a high-level African Union mission to speed up the International Criminal Court's arrest warrant for President Omar al-Beshir for war crimes, Chadian state radio said Friday.

Refugees at a camp in Djabal in the east of Chad accused Beshir of causing "genocide, rape and pillage" and said they would not return to Darfur until peace is established between Khartoum and N'Djamena, the station added.

Their plea came as they met an AU delegation led by South African ex-president Thabo Mbeki, former Nigerian president Abdusalami Abubakar and Pierre Buyoya, the ex-Burundian president.

The delegation travelled to the east Chadian towns of Abeche, Goz Beida and Djabal on Thursday as part of its efforts to help broker peace talks in neighbouring Sudan's Darfur province, the radio station added.

Diplomatic relations between Chad and Sudan are severely strained, with each accusing the other of supporting rebel movements in its territory.

Several hundred Sudanese refugees have fled across the border to escape the conflict in Darfur, for which the international community has largely blamed the Khartoum government.

The ICC on March 4 issued the warrant to arrest Beshir for alleged crimes against humanity and genocide in Darfur.

It accused him of criminal responsibility for "exterminating, raping and forcibly transferring large numbers of civilians" from Darfur, where the United Nations says conflict has cost 300,000 lives.

The Sudanese president denies the ICC's charges.