Last week the government signed a ceasefire deal with Karen rebels - who have fought for greater autonomy for more than 60 years.

The Government said the attack may have been the work of ethnic Karen rebels.

The government offensive against Karen rebels based along the Thai border escalated during March.

Meanwhile, fighting linked to the poll between ethnic Karen rebels and government forces has caused at least 15,000 people to flee into Thailand.

The ethnic Karen rebels' fight for greater autonomy has been one of the largest of the brutal civil wars in Myanmar.

There are rumours that the Karen rebels are regrouping in the jungle.

Continue reading the main story Who are Burma's Karen rebels?

They played a significant part in the capture of Manerplaw, a stronghold of the Karen rebels.

State media blame "insurgent destructionists", including ethnic Karen rebels.

Karen rebels join the fight to help Rambo and the mercenaries win.