UPDATE : 4 May 2011                     The Burmese army has opened fire on a Karen rebel stronghold located across the border from Umphang District of Tak Province. 
So far, more than 400 Burmese refugees have crossed the border into Thailand to escape the fighting.  
The Burmese government force has launched a new offensive against the  Democratic Karen Buddhist Army's stronghold located approximately 30  kilometers across the border from Umphang District in Tak Province.
More than 400 Burmese refugees, mainly women, children, and elders, have  crossed the border into Thailand to escape fierce fighting between the  two sides. 
Meanwhile, the Thai Border Patrol Police have positioned forces along  the border to prevent any possible incursion into Thai territory. 
The Thai authorities have relocated the refugees to a nearby temporary shelter.
Governor of Tak Province Samart Loyfah said he has ordered local  officials to offer humanitarian assistance, including food and water, to  the refugees. 
Once the fighting has subsided, they will be asked to return to Myanmar.
-- TAN Network --