Western diplomats shunned the opening ceremony of a conference in Qatar on Sunday attended by Sudan's president, who is wanted for war crimes by the International Criminal Court (ICC).
Omar Hassan al-Bashir, who came to power in Sudan in a 1989 Islamist and military-backed coup, has continued to travel abroad since the ICC charged him with genocide and crimes against humanity in 2008.
But his appearance on a list of speakers at a humanitarian conference in Doha on Sunday attended by the deputy head of the United Nations prompted the U.S., Canadian and Australian ambassadors to boycott the event, according to two Western diplomats in Doha.
Spokespeople for the three embassies did not immediately respond to a request for comment.
Three European diplomats who attended the event said they walked out before Bashir addressed the Doha Forum attended by the Gulf state's emir and U.N. Deputy Secretary-General Amina Mohammed.
"The Sudanese president is wanted by the ICC so it would not be appropriate to be present for his remarks," said one of the diplomats.
A UN official in Doha declined to comment on Bashir's attendance but said that the U.N. had attended the conference for over a decade in a "spirit of cooperation".
Qatar, which has brokered peace agreements in Sudan, is not a signatory to the Rome Statute that established the ICC, a court that has no means of enforcing its arrest warrant on its own and relies instead on states to do so.
Bashir denies the charges against him. Many African and Arab states, along with Sudan's key ally China, have called for the warrant to be suspended.
In March U.N. High Commissioner for Human Rights Zeid Ra'ad al Hussein said Jordan had broken its treaty obligations by hosting Bashir..
Sudan is seen as having drawn closer to Sunni Muslim Gulf states since it sent hundreds of Sudanese soldiers to Yemen in 2015 to bolster the mostly Gulf Arab alliance fighting the Iran-allied Houthi movement.