By Mohamed Sudam SANAA, May 13 (Reuters) - Yemeni forces, backed by tribesmen, have fought in recent days some of their toughest battles yet in a months-old conflict with Shi'ite Muslim rebels in the mountainous north of the country. The troops, with help from the tribesmen, retook a key government building in the Razih area on Sunday, a month after it was captured by followers of Shi'ite rebel leader Abdul-Malik al-Houthi. They also pushed the rebels from the town Qalaa. Authorities declined to give the number of casualties in that operation, but a local official said some 40 soldiers and tribesmen were killed. He said around 20 rebels were also killed and 15 captured, but dozens more fled. The government officials said intense fighting also broke out south of Saada, ending almost a week of relative calm after local tribes pledged to fight Houthi's followers and government forces prepared to change tactics as the conflict dragged on. Thousands of people have fled their homes in the latest bout of the conflict, which has been raging on and off since 2004. The rebels oppose Yemen's close alliance with the United States and the government says they want to reinstall the Islamic Imamate that was overthrown in 1962. Sunnis make up most of Yemen's 19 million people, and most of the rest belong to the Zaidi branch of Shi'ite Islam. The officials said government forces were now mounting simultaneous attacks on all rebel strongholds in an effort to prevent them from fleeing to other areas. It was not immediately possible to get a comment from Houthi. The official Socialist Party Web site, seen as sympathetic to Houthi, said it had information that Qatar was mediating to end the conflict. There was no official comment from Qatar, whose emir visited Sanaa last week. The government official said battles that took place on Thursday and Friday were among the most intense since the hostilities flared up again in January. Houthi's followers attacked army barracks, and dozens were killed in ensuing battles, local officials and witnesses said. The conflict has proven costly for both sides. A senior Yemeni security source told Reuters that around 600 of Houthi's followers and 450 soldiers had been killed from the outbreak of the conflict until Wednesday. More than 3,000 people have been wounded on both sides, the source said.
