Clashes have erupted in eastern Burma only weeks after a ceasefire was signed between the government and opposition Shan State Army (SSA).

The fighting broke out earlier this week after Shan troops encountered three Burmese battalions. The SSA had been attempting to cross through its own territory northwest of the town of Tachilek, on Shan state’s border with Thailand.

Khunsai Jaiyen, editor of Shan Herald Agency for News, said that the Burmese battalions on 7 February had blocked the exit routes for SSA soldiers, who had been pressured by the government to retreat into their existing territory while both sides begin the complex process of demarcating zones of control.

He added that other skirmishes had taken place in Mongpyin township in eastern Shan state after the Burmese attacked a nearby SSA outpost. The SSA has reportedly written to the regional military command centre detailing the incidents, and has put its frontline troops on alert.

The fragility of Burma’s recent ceasefires has become increasingly apparent – clashes broke in Karen state last month, only weeks after the government held ceasefire talks with the Karen National Union.

The SSA has voiced concern about the finer details of their agreement with Naypyidaw’s ‘peace-making committee’, which includes allowing Burmese troops to pass through their territory given prior permission.

The group this week also warned that any ceasefire would be meaningless unless the military ends abuse of civilians in the volatile eastern state, which for decades has shouldered the burden of armed conflict and the fallout from its status as a lucrative source of narcotics.

The SSA’s conflict with the central government stretches back nearly half a century. Shortly after it was formed in 1964 it split into two factions, with what came be known as the Shan State Army–North (SSA-N) allying itself with the government.

That relationship appeared to be on the rocks last year after fighting broke out between Burmese troops and the SSA-N, following the latter’s refusal to become a Border Guard Force.

But in late January the SSA-N also agreed a truce with the government, and both factions await further negotiations regarding territory.