(Adds Bush departure, paragraph 8) By Caren Bohan and Tsvetelia Ilieva SOFIA, June 11 (Reuters) - President George W. Bush said on Monday it was a high priority for the United States to win the release of five Bulgarian nurses sentenced to death in Libya for infecting children with HIV. Ending an eight-day European tour in Bulgaria, Bush also called for an exchange of information with Russia on the planned U.S. missile defence shield in central Europe and said he regretted the collapse of an immigration bill back home. "We strongly support the release of the Bulgarian nurses in Libya," Bush told a news conference in Sofia. "It's a high priority for our country." "Together with the EU, the United States is contributing to a fund to provide assistance to the Libyan children suffering from this disease (HIV/AIDS) and to their families." Bulgarians have expressed hope that Bush's intervention would provide the final push to help bring home the five nurses and a Palestinian doctor who were convicted in December of deliberately infecting 426 children with HIV. Their highly politicised trial has hampered attempts by OPEC member Libya to restore full relations with the West. In Tripoli, EU Commissioner for External Relations Benita Ferrero-Waldner said she saw "a window of opportunity" for the release of the six medics, in jail since 1999. They say they are innocent and were tortured to make them confess. Bush flew home from Sofia on Monday afternoon, having visited the Czech Republic, Germany, Poland, Italy, the Vatican, Albania and Bulgaria. In Sofia, Bush shook hands and chatted with a group of Bulgarians in central Nevski Square, but there was no outpouring of affection he encountered in Albania on Sunday. MISSILE SHIELD During the European trip Bush sought to bolster ties with Western leaders at a G8 summit, but the trip was dogged by U.S.-Russian tensions, exacerbated by planned U.S. missile defence bases in Poland and the Czech Republic. Bulgarian President Georgi Parvanov said Bulgarians should not have to choose between the United States and Russia. "The same way I am friends with George and Vladimir (Putin), we could keep good relations with both ... without losing our strategic priorities," he said. Putin turned the tables on Washington at the G8 summit last week by proposing the United States drop the plan and instead use data from a Russian-operated radar in Azerbaijan. Bush said he had called for U.S. and Russian experts to analyse each other's proposals and he thought collaboration and sharing information "will be beneficial". Bush and Putin will meet next month at the U.S. president's family retreat in Kennebunkport, Maine. TROUBLES BACK HOME At home, Bush will face difficulties on key domestic issues such as the collapse of legislation to overhaul immigration and Senate Democrats considering a no-confidence vote on his top law enforcement official, Attorney General Alberto Gonzales. A bipartisan immigration compromise unravelled in the Senate last week in the face of opposition from the both ends of the political spectrum, including Bush's fellow Republicans. "I was disappointed that the bill was temporarily derailed," Bush said in Sofia. "We made two steps forward on immigration, we took a step back, and now I'm going to work with those who are focused on getting an immigration bill done and start taking some steps forward again," he said. "I believe we can get it done." Bush insisted Gonzales would stay in his administration regardless of the planned no-confidence vote. Gonzales, a long-time friend of Bush, has drawn sharp criticism for the handling of the firing of nine U.S. prosecutors last year. "There's no wrongdoing," Bush said. "And I'll make the determination if I think he's effective, or not, not those who are using an opportunity to make a political statement on a meaningless resolution." (Additional reporting by Jan Lopatka and Tabassum Zakaria)
