YANGON, April 29 (Xinhua) -- Myanmar Prime Minister General Thein Sein left the new capital of Nay Pyi Taw for Bangkok Tuesday afternoon to start an official visit to Thailand aimed at enhancing ties and cooperation between the two southeastern Asian neighbors.

    Accompanied by high-ranking government officials from foreign affairs, national planning and economic development, labor and transport, Thein Sein's three-day trip is a return visit by his Thai counterpart Samak Sundaravej last month.

    The two prime ministers will hold talks in Bangkok mainly on enhancement of bilateral economic cooperation.

    Samak's March visit to Myanmar was the first as Thai prime minister after he led the People Power Party to victory in last December election and took office in early February this year.

    During that visit, Myanmar and Thailand signed an agreement on promotion and protection of investments between the two countries

    Myanmar-Thailand bilateral cooperative ties have maintained a good momentum in recent years with Thailand playing a key role in Myanmar's economic development as Thailand has become Myanmar's biggest foreign investor and trading partner.

    With huge investment of 6.311 billion U.S. dollars pouring in Myanmar's electric power sector alone, Thailand's investment has accounted for 7.3 billion dollars or over 53 percent of Myanmar's total foreign investment received.

    The Thai investment prompted Myanmar's contracted foreign investment to hit 14.736 billion U.S. dollars in 19 years as of the end of 2007 since the country opened to such investment in late 1988.

    Thailand also stood as Myanmar's top trading partner as well as top exporting country during the fiscal year 2006-07 with a bilateral trade volume of 2.659 billion U.S. dollars of which Myanmar's export to Thailand amounted to 2.409 billion dollars. The bilateral trade accounted for over 30 percent of Myanmar's total foreign trade which reached nearly 8 billion dollars in the year. Myanmar gained a trade surplus with Thailand for exporting natural gas during the year.

    In 2006-07, Thailand also had 248 million dollars worth of border trade volume with Myanmar.