Unidentified gunmen have attacked two oil tankers on a train in a border area between Thailand and Burma, near where a series of bomb explosions killed four people on Wednesday.
Thai security officials say the tanker attacks happened early Thursday near Burma's Tachilek town, opposite the town of Mae Sai in Thailand. The Associated Press quotes a local resident who said one of the tankers was destroyed.
An exact number of casualties is not known.
In Wednesday's bombings, two policemen were among the four people killed.
There was no immediate claim of responsibility for the explosions, but Burmese authorities say they suspect ethnic Shan rebels are to blame. The Shan rebels are among several ethnic groups that have been seeking autonomy from Burma's military government.
Information for this report is provided by AP.