Thailand's military-appointed Prime Minister Surayud Chulanont and top Chinese leaders on Monday vowed to maintain the close relationship between their two nations, despite the possibility of more political turmoil in Thailand, DPA reported. Surayud met President Hu Jintao and Premier Wen Jiabao on the first day of a two-day visit to China that was cut short to allow the Thai premier to rush back in time for a controversial Constitutional Tribunal ruling on Wednesday. The tribunal could dissolve Thailand's two largest political parties, throwing the kingdom into further political turmoil. Hu said China would continue to treat Thailand as a "closest and trusted friend", whatever the future brought. "We respect the development path chosen by the Thai people," state television quoted Hu as telling Surayud. "No matter what kind of changes happen in the international affairs, or in the internal affairs of the two countries, our principle of friendship between China and Thailand will not change," he said. Surayud and Wen agreed to expand cooperation in areas including investment, defence, culture, education, disease prevention, and the fight against drug-trafficking. They promised to make more effort to realise the goal of bilateral trade worth 15 billion dollars by 2010, state television said. The two sides also signed a 15-point Joint Strategic Plan of Action between the two Asian nations for 2007-11.