ANKARA (AFP) - US Defence Secretary Leon Panetta arrived Thursday in "key ally" Turkey from Iraq, for an official visit that will focus on the developments in the Middle East, especially Syria. "It's important for us to work closely with Turkey at this critical time," Panetta told reporters shortly before his arrival in Ankara for the two-day visit. The discussions between Panetta and Turkish officials will "focus on the turmoil and the change sweeping the immediate neighbourhood and the increasingly close collaboration that... (US) had with Turkey in supporting the transition in Iraq, Egypt, Libya and also confronting the (Syrian) regime," a senior US official said.