Aid workers called Thursday for a ceasefire to allow the evacuation of people trapped around a town at the centre of fierce fighting between Myanmar's army and ethnic rebels, after the deaths of two more civilians in an area cloaked in a state of emergency.

Tens of thousands of civilians have already fled the remote and rugged Kokang area of northeastern Shan State over the last 10 days, with at least 30,000 crossing the border into China.

Local aid groups have officially suspended rescue convoys to and around the flashpoint town of Laukkai, where a series of surprise attacks by ethnic Kokang rebels last week sparked the flare up of violence.

The decision follows an attack on a convoy led by the Myanmar Red Cross that wounded two aid workers on Tuesday. Officials say the roads leading to the area may have been mined by the rebels.

"We still do not know exactly how many people are still trapped in the Laukkai region... but we evacuated around 30 people from there on Wednesday," a Myanmar Red Cross member told AFP in the Shan town of Lashio, some 140 kilometres (85 miles) south of Laukkai.

"We are asking both sides to keep a ceasefire for a few days, so we can help to evacuate people. Currently, even our Red Cross logo cannot help to protect people. It's really sad."

Over recent days fighting has clustered just south of Laukkai -- after the town was effectively emptied by the outbreak of conflict last week, which saw nearly 50 Myanmar soldiers killed in a rebel assault.

The army regained the town after helicopter and jet air strikes were followed by bloody street gun battles, which state media said killed dozens of rebels.

- Rebel ambushes -

Rebels have continued to carry out sporadic ambushes with "small and heavy weapons" on army convoys and camps but have withdrawn "when counterattacks were launched", state-led newspaper Global New Light of Myanmar reported Thursday.

"Three tatmadaw (army) personnel died in action and two civilians," the report said, adding affiliated rebel groups, including the Ta'ang National Liberation Army and the powerful Kachin Independence Army, had also carried out attacks.

Rebels have said they are braced for a major army assault, after Myanmar imposed a state of emergency handing a local military commander sweeping powers.

An MP for Laukkai said his constituency was a virtual ghost town, with only a few residents left guarding their houses.

"People dare not to come back to the town," said Kyaw Ni Naing, an ethnic Kokang MP for Laukkai told AFP from the capital Naypyidaw.

"We do not want to see any fighting. I want my region to be in peace as soon as possible," he said, adding the refugees in China are desperate to return, but they "have to wait until the fighting stops".

While the majority of the fleeing civilians have crossed into southwest China, tens of thousands more are believed to have been displaced on the Myanmar side of the border.

Several thousand have streamed into Lashio where they are seeking sanctuary in a cramped monastery.

Experts say Kokang area is viewed in Myanmar as a culturally distinct outpost, renowned for drug production and a cross-border trade with China.

Many of the ethnic Kokang are of Chinese origin.

China says it is providing relief to the refugees but has urged a swift end to the conflict.

Officials have blamed the Kokang rebel leader Phone Kya Shin for the sudden flaring of violence -- after six years of relative calm -- and called on Beijing to rein in any local officials who might be helping the group on its side of the border.

Myanmar's President Thein Sein has vowed "not to lose an inch of Myanmar's territory" to the rebels.

But the violence has undercut his well-trailed attempts to secure a nationwide ceasefire to end several festering insurgencies before breakthrough elections are held later this year.