PARIS -- Sudan's president, Omar Hassan al-Bashir, made a brief appearance at an African Union summit meeting in Nigeria but vanished after human rights groups filed a lawsuit calling for his immediate detention on an international arrest warrant for charges of genocide.
Mr. Bashir had arrived in the Nigerian capital, Abuja, for a two-day meeting on health issues with other African heads of state and attended Sunday night's opening reception. But delegates at the conference said that in the middle of an official lunch on Monday, he abruptly left the room. During the afternoon session, when Mr. Bashir was scheduled to speak, he could not be found.
A Sudanese Embassy spokesman said Mr. Bashir had left Abuja by 3 p.m. that day. He arrived in Khartoum, Sudan, on Monday night.
A government spokesman denied that the president's early departure had anything to do with the threat of being arrested.
"Most presidents don't attend entire conferences, and he had matters to attend to in Khartoum," the spokesman, Iman Sid Ahmad, said.
But Nigeria appeared to be the latest hurdle in Mr. Bashir's travel plans since the International Criminal Court in The Hague issued the warrant for him in 2009. The court ordered him to face charges of war crimes and crimes against humanity after a campaign of killing, torture and rape against civilians in the Darfur region, where about 300,000 people died and more than two million were uprooted in years of fighting between the government and rebels. Judges later added three counts of genocide.
Countries that are signatories to the court, Nigeria included, are obligated to honor its warrants. On Monday, judges in The Hague issued a statement reminding Nigeria of its responsibilities.
But a Nigerian government spokesman, Rueben Abati, defended the decision to welcome Mr. Bashir at the meeting. "Nigeria is just hosting it," Mr. Abati said. "It's not Nigeria that invited him. He is here to participate in an African Union summit, and Nigeria is not in a position to determine who attends an A.U. event and who does not attend."
Human rights groups in Nigeria had agitated against Mr. Bashir's visit, and on Monday morning, as the meeting began, lawyers filed a suit with the Federal High Court in Abuja demanding that he be handed over to the international court.
"We don't want him in Nigeria, except for him to be arrested," Chino Obiagwu, one of the lawyers involved, said in a phone interview from Abuja. "We are fighting for the victims in Darfur. We don't want him here for a conference or for a holiday."
Mr. Bashir has denied the charges against him and has retorted with a public campaign to try to undermine the international court, accusing it of bias because all of its cases are against Africans.
He has made a point of traveling outside Sudan to show that his critics have not succeeded in isolating him. But while he has been received in some countries, including China, Egypt, Chad and Qatar, others, including South Africa, Uganda and Turkey, have disinvited him to international gatherings.
Mr. Bashir has stopped his customary visits to the United Nations in New York. And in one embarrassing episode, he arrived a day late in 2011 to an official visit to Beijing after his plane was forced to turn back while in Turkmenistan airspace.
On the sidelines of the summit meeting in Abuja, Mr. Bashir met with the presidents of Nigeria, Ethiopia and Kenya, according to Mr. Ahmad, his spokesman. "They discussed matters relating to the conference, Sudan and South Sudan and Africa," he said.
Mr. Bashir has something in common with Kenya's president, the recently elected Uhuru Kenyatta. He, too, has been ordered to stand trial at the International Criminal Court. Mr. Kenyatta faces charges of crimes against humanity in connection with the waves of violence after Kenya's disputed 2007 elections.
Mr. Kenyatta has not been served with an arrest warrant because he has pledged to cooperate with the court.
Isma'il Kushkush contributed reporting from Khartoum, Sudan.
This article originally appeared in The New York Times.