One of Egypt's most prominent dissidents, who was jailed after challenging the country's longtime president in the 2005 elections, was freed Wednesday in a surprise move that came after years of pressure from the United States to release him. The jailing of Ayman Nour has been sticking point in Egyptian-US relations for more than three years, and his sudden release may be a gesture to improve ties with US President Barack Obama's new administration. Nour told The Associated Press from his Cairo home that he had not been notified of his release until a car came to pick him up at his prison and brought him home. "Why they did this is unknown. ... I am coming out with an open heart and am ready to work and nothing has changed. A lot of things have been put on hold over the past years," he said. The prosecutor's office said in a statement that Nour had been ordered released for health reasons. While in prison, Nour has complained of heart and eye problems, and his wife had petition Egyptian courts for his release on health grounds. Nour, who is in his mid-40s, challenged Egyptian President Hosni Mubarak in the September 2005 presidential elections, but finished a distant second in balloting criticized as flawed and in which most voters stayed away. Nour, who headed the opposition Al-Ghad party, was convicted Dec. 24, 2005, of forging signatures on petitions to register the party in 2004. He said he was prosecuted to eliminate him from politics, and the argument received wide support among human rights groups. Former President George W. Bush specifically named Nour among several dissidents from other countries - including Cuba and Burma - during a speech in June 2007 in the Czech Republic that lauded democracy's progress around the globe. "There are many other dissidents who could not join us because they are being unjustly imprisoned or held under house arrest. I look forward to the day when conferences like this one include ... Ayman Nour of Egypt," Bush said at the time. In August, Nour wrote a letter to then-Presidential candidate Obama, urging him to help Arab reformers push for democracy in the Middle East. In the letter, Nour said Obama "embodies the dreams of Arab reformers for democracy and change." Nour's wife said at the time that the letter was sent to Obama's campaign e-mail address. It was also published in August in an independent Egyptian newspaper, Al-Masry Al-Youm.