Vietnamese Prime Minister Nguyen Tan Dung will pay an official visit to Laos on Sept. 9-10, at the invitation of his Lao counterpart Thongsing Thammavong, and will co-chair the Vietnam-Laos conference on cooperation and investment, reported Vietnam News Agency on Wednesday. The visit, the first overseas trip by Dung since he has been re- elected by the Vietnamese National Assembly as the government prime minister this July, re-confirms Vietnam\'s consistent policy to attach importance to and develop the special and comprehensive relations with Laos, said the report. Vietnam-Laos traditional and comprehensive relationship has been finely developed. The two sides maintain regular exchange of high-ranking visits, with the most recent ones to Laos by Vietnamese Party General Secretary Nguyen Phu Trong in June 2011, and to Vietnam by Lao Prime Minister Thongsing Thammavong in March 2011, Lao Party General Secretary and President Choummaly Sayasone in August 2011, and Lao National Assembly President Pany Yathotu in late August 2011. Vietnam is among the leading foreign investors in Laos, to date having 252 projects worth 3.2 billion U.S. dollars. Vietnam is Laos\' third biggest trade partner after Thailand and China. Two-way trade turnover reached 490 million U.S. dollars in 2010, and 402.3 million U.S. dollars in the first seven months of 2011. Both sides agreed to reach a trade turnover of two billion U. S. dollars by 2015. The two countries have also close coordination at international forums, including exchange of information about international issues of mutual concern, joint activities in the ASEAN community and the Mekong sub-region. Vietnam shares with Laos experience in hosting international events and preparing for the latter\'s access to the World Trade Organization (WTO). Leaders of the two countries agreed to make 2012 as the \" Vietnam-Laos friendship and solidarity year\".