Journalists arrested in Myanmar after soldiers fire at protesters

Myanmar security forces fired on a protest and arrested journalists in the country's north on Sunday as reports of troop movements suggested an impending crackdown on demonstrations against a recent military coup.

The junta has recently escalated efforts to quell a burgeoning civil disobedience campaign demanding a return of the country's ousted leader Aung San Suu Kyi.

Soldiers fired tear gas then shot at a crowd who gathered in Myitkyina to stop a rumoured shutdown of the northern city's electricity grid.A journalist at the scene said it was unclear how many had been injured in the incident.

"We don't know if police had used rubber bullets or live rounds," the reporter added.

Police later arrested at least five journalists reporting from the scene, according to a media outlet based in the city.

Armoured vehicles were briefly seen on the streets of commercial hub Yangon late in the afternoon, and social media footage has since shown other troop deployments.

A joint statement from the US, British and European Union ambassadors urged security forces not to harm civilians.

"We call on security forces to refrain from violence against demonstrators, who are protesting the overthrow of their legitimate government," said a statement signed by the European Union and Britain.

The US embassy advised American citizens to shelter in place and warned of another potential nationwide internet blackout.

"There are indications of military movements in Yangon and the possibility of telecommunications interruptions overnight," the mission's consular section said in a statement.

Much of the country has been in uproar since soldiers detained Aung San Suu Kyi and her top political allies, ending a decade-old fledgling democracy after generations of junta rule.

The Nobel laureate, who spent years under house arrest under an earlier dictatorship, has not been seen in public since she was detained on February 1 alongside top aides.

Security forces have arrested some people joining a civil disobedience movement that has seen huge crowds throng big urban centres and isolated frontier villages alike.

At least 400 people have been detained since the coup, the Assistance Association for Political Prisoners monitoring group said.

But fear of arrest did not deter big crowds from returning to streets around the country for a ninth straight day of street protests on Sunday.

In the southern city of Dawei, seven police officers broke ranks to join anti-coup protesters, mirroring local media reports of isolated defections from the force in recent days.

Parts of the country had in recent days formed neighbourhood watch brigades to monitor their communities overnight -- in defiance of a junta curfew -- and to prevent the arrests of residents joining the civil disobedience movement.

"We don't trust anyone at this time, especially those with uniforms," said Myo Ko Ko, a member of a street patrol in Yangon.

Near the city's central train station, residents rolled tree trunks onto a road to block police vehicles and escorted away officers who were attempting to return striking railway employees to work.

The country's new military leadership has so far been unmoved by a torrent of international condemnation.

An emergency session of the UN Human Rights Council on Friday called for the new regime to release all "arbitrarily detained" people and for the military to hand power back to Suu Kyi's administration.

The junta insists it took power lawfully and has instructed journalists in the country not to refer to itself as a government that took power in a coup.

It also instructed reporters in Myanmar "not to write to cause public unrest" while reporting events in the country.