OSH, Kyrgyzstan - The deposed president of Kyrgyzstan left the country Thursday for neighboring Kazakhstan, allaying fears of a civil war in the Central Asian nation, which hosts a key U.S. military base supporting the war in Afghanistan. The presidents of the United States, Russia and Kazakhstan helped arrange for Kyrgyz President Kurmanbek Bakiyev to leave the country, Kazakhstan said in its role as the rotating chair of the Organization for Security and Cooperation in Europe. It called Bakiyev's move "an important step toward ... the prevention of a civil war in Kyrgyzstan." Kyrgyzstan's provisional leaders said Bakiyev had signed a formal letter of resignation. Witnesses said Bakiyev flew out from the southern city of Jalal-Abad in a military transport aircraft. The Kremlin said later that the Russian Defense Ministry arranged the flight. Bakiyev's departure followed the provisional government's warning that he should leave quickly or face trial. "He had to leave the country because he was afraid of people's justice," deputy head of the new government, Omurbek Tekebayev, told The Associated Press. Bakiyev was driven from the capital, Bishkek, on April 7 after police opened fire on protesters, who then stormed government buildings. At least 83 people died in the violence. He fled to Kyrgyzstan's south, his clan power base, and began to rally support, prompting fears that the impoverished country might split into two. But his efforts suffered a severe blow early Thursday when he tried to speak to a rally in Osh, the region's biggest city. Within a few moments of his taking the stage, gunfire split the air and he was hustled into a car and driven away. Witnesses said the shots came from his bodyguards who may have been frightened by a group of Bakiyev opponents approaching the rally. Although there were no reports of injuries, the incident was a humiliating setback to Bakiyev's effort to claim he is still the legitimate president. Bakiyev had said earlier he would be willing to resign if security guarantees were given to him and close relatives. The interim authorities offered him such guarantees but refused them for his family. Bakiyev's opponents have blamed him and his family for last week's violence, as well as for rampant corruption and other abuses. Another member of the interim government in Bishkek, Tobchubek Turgunaliyev, said Bakiyev was accompanied on the flight to Kazakhstan only by his wife and two small children. Turgunaliyev told the AP that Bakiyev's former defense minister has been arrested. An operation is under way in the south to arrest Bakiyev's brothers, one of whom, Zhanybek, the presidential guards chief, has been accused by the opposition of issuing the order to fire at protesters in Bishkek. Another brother of the ousted president, Kamnybek, speaking later from their home village of Teyit, told the AP that "everything is quiet" there. He said the former defense minister had voluntarily turned himself in to the authorities to avoid bloodshed. Bakiyev spoke late Wednesday by telephone with Russian Prime Minister Vladimir Putin. Putin's office didn't release any details of the conversation, but he had earlier offered strong backing to Bakiyev's foes. Bakiyev's departure raised hopes for a quick settlement of the crisis in the former Soviet republic, which hosts a U.S. air base at the capital's airport. The Manas base has resumed full operations, the U.S. Embassy said in a statement Thursday.