Several bases belonging to the Shan State Army (SSA) in eastern Burma have been evacuated following a week of heavy fighting close to Kehsi township, as Burmese forces continue to advance on the insurgent group.

Sources close to the SSA claimed the group moved due to the human costs of conflict on the surrounding civilian population, with Burmese shells said to have hit villages close to Kehsi in southern Shan state.

A heavy barrage of attacks on SSA positions in Nampook, Loikong, Loihsai and Hpatnam since 11 July has increased pressure on the group as it struggles to keep hold of Wanhai, the headquarters of the SSA’s northern faction.

Shan leaders accused the Burmese army last week of using fighter jets to bomb positions around Wanhai, a rare occurrence in the central government’s decades-long conflicts with ethnic armies in the border regions.

Sai Hla, spokesperson of the SSA, said that around 1000 Burmese troops are currently advancing toward Wanhai as of 3pm on Saturday last week, following the group’s decision to pull out from several bases.

“They fired artillery in the hills and a lot of shells landed in [nearby] villages so we decided to withdraw,” he told DVB. “Now they are close to Wanhai – about eight miles away. I think there will be serious fighting again if they get closer.”

Fighting has raged between both sides since the SSA’s refusal to become a government-controlled Border Guard Force (BGF), escalating around March this year. The once disparate SSA-South and SSA-North also rekindled an alliance in May this year, and are both engaged in fighting against government troops.

More than 1000 people are believed to have fled the fighting in southern Shan state, among them 700 pupils from primary and secondary schools in Hpatnam, Kenglonm, Wanhai and Parkhee townships.

A number of schools have been closed since fighting began, and local government officials reportedly evacuated teachers to Mongshu town.