Ethnic armed forces in Myanmar say they've occupied a military base near the border with Thailand.

The Karen National Union made the announcement on Thursday, saying the facility lies close to the town of Myawaddy. The group also released photos of rifles and ammunition found on site.

The KNU says that the junta's troops who were stationed at the base have retreated to a bridge connecting Myanmar with Thailand.

Ethnic armed forces and pro-democracy fighters in Myanmar have maintained a fierce assault against the military since October.

The fighting approached the Thai border earlier this month. The military responded to the KNU's assault with air strikes.

Local media say the junta is believed to have deployed a convoy of troops to the region, raising fears about even more bloodshed.