YANGON: Myanmar's junta deployed extra troops around the country and choked the internet on Monday as it intensified a crackdown on anti-coup protests, but defiant demonstrators again took to the streets.

The military has steadily escalated efforts to quell an uprising against their seizure of power two weeks ago, which saw civilian leader Aung San Suu Kyi detained along with hundreds, including members of her democratically elected government.

Suu Kyi and President Win Myint -- who have not been seen in public since the coup -- are expected to be questioned by a court "via video conferencing" in the country's capital of Naypyidaw this week, said lawyer Khin Maung Zaw, adding he has not been able to make contact with either client since they were detained in dawn raids.

The generals imposed an hours-long internet shutdown on Monday morning and ratcheted up the military's presence across the country overnight, including armoured vehicles in Yangon, the nation's commercial hub and biggest city.

Fresh protests -- though much smaller than in previous days -- again flared in the city, including near the central bank where troops were deployed.

"Patrolling with armoured vehicles means they are threatening people," said 46-year-old Nyein Moe, among the more than 1,000 gathered in front of the bank.

"People are marching on the streets and they don't care to be arrested or shot. We can't stop now. The fear in our mind is going away."

By afternoon, thousands had gathered outside the Chinese and US embassies in Yangon, carrying signs that say "Get out dictator" and "We need US army to save our situation."

There was a fresh rally in the southern city of Dawei too, a verified live stream on Facebook showed, with hundreds of protesters accompanied by a marching band.

Some carried banners against the military that read: "They kill in (the) day. They steal at night. They lie on TV."

A Naypyidaw protest on Monday led by high school student groups was met with use of force after they had retreated, the students told AFP. Police also arrested dozens of the young protesters.

"We were peaceful and even apologised... but then they fired water cannon," a high school student told AFP, refusing to provide a name for fear of repercussions.

"We tried to resist it at first, but then they forcefully hit us with batons."

Monitoring group NetBlocks reported that a "state-ordered information blackout" had taken Myanmar almost entirely offline early Monday.

Internet connectivity was later restored around the start of the working day, with Netblocks saying the blackout lasted around eight hours.

Intensifying fears the military was going to impose a far harsher crackdown, troops in the northern city of Myitkyina fired tear gas then shot at a crowd on Sunday night.

A journalist at the scene said it was unclear whether police had used rubber bullets or live rounds.

Local media outlets said at least five journalists monitoring the protest were detained and released Monday.

Much of the country has been in uproar since soldiers detained Suu Kyi and her top political allies on February 1, ending a decade-old fledgling democracy after generations of junta rule.

An internet blackout last weekend failed to quell resistance that has seen huge crowds throng big urban centres and isolated frontier villages alike.

So far, 400 people -- including striking workers -- have been detained since the coup, according to the Assistance Association for Political Prisoners monitoring group.

Parts of the country have in recent days formed neighbourhood watch brigades 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, member of a street patrol in Yangon.

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

UN Secretary-General Antonio Guterres echoed that call. Through his spokesman, he also asked the military to "urgently" allow Swiss diplomat Christine Schraner Burgener to visit Myanmar "to assess the situation first hand".

UN special rapporteur Tom Andrews said the junta's efforts to rein in the burgeoning protest movement was a sign of "desperation" and amounted to a declaration of war against its people.

"Attention generals: You WILL be held accountable," he tweeted.

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

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