Growing Chinese investments in Burma are being threatened by Burmese military operations against ethnic Chinese tribesmen (the United Wa Army) living near the Chinese border. An army offensive last year sent nearly 40,000 Wa refugees into China. The Chinese did not like this, and were not able to control the news (of ethnic Chinese being "oppressed" by Burmese troops). The details got out via the Internet and people texting each other. While that sort of thing is no problem in Burma (which has much tighter censorship than China), the Chinese want the Burmese to calm down. To that end, some senior Chinese officials are going to visit Burma, to work out these problems. China considers Burma a valuable ally and client state. As a political outcast to most of the world, Burma needs this Chinese support. There is an informal ceasefire between the Wa and the Burmese troops, but fighting could break out at any time.
In the north, non-Chinese Karen tribes, that had made a peace deal with the government, are now having second thoughts. Over the last two decades, the government has worked out peace deals with many of the northern tribes (that were never really part of "Burma", but were incorporated in British colonial Burma, which became independent right after World War II.) But these peace deals have not gone well, as there is not a lot of love between the ethnic Burmese and the tribes (who are a mixed bag of ethnicities.) So some factions of the Karen army are resisting the Burmese army once more.
May 15, 2010: A Thai soldier was shot dead by Burmese troops along the border. The killing was the result of a dispute with a group of Burmese soldiers seeking to get two of their number, who had been injured by a landmine, to an aid station. The Thai soldiers were in a boat, and refused the Burmese request to turn around and take the wounded soldiers to the Burmese military camp (and medical care). An argument broke out, and one of the Thai soldiers was shot dead. The river is the border.