US Secretary of State Hillary Rodham Clinton arrived in Ankara on Saturday. Clinton is expected to discuss withdrawal of US troops from neighboring Iraq as well as Turkey's contribution to Afghanistan's security and mediation for peace in the Middle East. She will meet the prime minister, foreign minister and the president on Saturday. Turkey is a supply route for US troops in Iraq and Afghanistan and ties have improved after hitting a low in 2003, when Turkey refused to allow US forces use Turkey as a staging ground for the invasion that toppled Saddam Hussein. Ankara says it is now ready to serve as an exit route for US troops pulling out of Iraq.