RAMADI, Iraq, March 13 (Reuters) - Iraq's Shi'ite Prime Minister Nuri al-Maliki flew to the western city of Ramadi on Tuesday on his first visit to the heartland of the Sunni Arab insurgency fighting his U.S.-backed government. Maliki, who flew accompanied by reporters, met with tribal leaders, local government officials and commanders of Iraqi and U.S. security forces in Ramadi, 110 km (68 miles) west of Baghdad. The highly symbolic visit to the capital of Anbar province, his first since taking office in May 2006, comes as thousands of U.S. and Iraqi troops are being deployed in Baghdad in a security plan that is seen as the last chance to avert a civil war.