Much of the country has been in open revolt since troops deposed civilian leader Aung San Suu Kyi on February 1, with disparate strands of Myanmar society uniting to protest against a return to military rule.

Security forces have steadily stepped up the show -- and use -- of force, by deploying troops against peaceful protesters, and firing tear gas, water cannon and rubber bullets.

A rally on February 9 in Myanmar's capital Naypyidaw turned violent when police fired rubber bullets at demonstrators, though doctors at the hospital later told AFP that at least two people had been critically wounded by live rounds.

Mya Thwate Thwate Khaing, who turned 20 last Thursday as she lay unconscious in a hospital bed, was shot in the head. A doctor confirmed her death Friday, adding that her body will be examined as it is a "case of injustice".

The young protester, a grocery store worker, is the first official death from the anti-coup movement since hundreds of thousands started gathering across the country two weeks ago to protest Myanmar's return to military rule.

She has become a symbol of resistance for protesters, who have hoisted her photos high in demonstrations and even unfurled a massive banner of artwork from a bridge showing the moment she was shot.

Her sister Poh Poh told reporters on Friday: "Please all join this protest movement to be more successful. That's all I want to say."

The European Union -- whose foreign ministers will meet Monday to discuss measures against the generals -- extended its sympathy to Mya Thwate Thwate Khaing's family and friends, said spokeswoman Nabila Massrali.

The EU also "reiterates its call on Myanmar's security forces to refrain from violence against demonstrators protesting against the overthrow of their legitimate government," she added.

The United States meanwhile condemned "any violence against the people of Burma", State Department spokesman Ned Price told reporters using Myanmar's former name, and reiterated "our calls on the Burmese military to refrain from violence against peaceful protesters".

Military spokesman-turned-deputy information minister Zaw Min Tun had said earlier this week that authorities were investigating the case of Mya Thwate Thwate Khaing.

He also said a police officer had died in Mandalay after a confrontation with protesters Sunday.

- Sanctions from UK, Canada -

Mya Thwate Thwate Khaing's death comes after an overnight announcement from Britain -- Myanmar's former colonial power -- and Canada that several generals would be sanctioned over their roles in the junta's security forces.

Freezing the assets of three top generals, the UK also said it was beginning a review to stop British businesses working with the military.

Canada sanctioned nine Myanmar military officials and accused the junta of engaging "in a systemic campaign of repressions through coercive legislative measures and use of force".

These actions come after US President Joe Biden last week announced Washington would cut off the generals' access to $1 billion in funds in the US.

- Internet shutdowns and arrests -

Early Saturday, NetBlocks announced "a sixth consecutive night under internet curfew" with service cut at 1:00 am (1830 GMT Friday). It also reported that Wikipedia had been blocked in all languages in the country.

On Friday tens of thousands -- including railway workers and teachers dressed in their uniforms to show they were boycotting work -- amassed across Yangon, Myanmar's largest city, carrying posters of Suu Kyi that read "Free our leader".

"Don't go to the office!" they chanted. "Go strike! Go strike!"

In the northern city of Myitkyina, a small group of protesters was forcefully dispersed by police and military wielding batons, according to video posted online and witnesses.

One teacher who was there -- and is now in hiding for fear of arrest -- said she saw dozens arrested in the scuffle, including two of her colleagues.

"They arrested those who tried to take photos and videos... this is real injustice," she told AFP.

Before Friday, more than 520 people had been arrested, according to the Assistance Association for Political Prisoners (AAPP) monitoring group, many of them civilians taking part in the so-called "Civil Disobedience Movement".

The junta has justified its power seizure by alleging widespread electoral fraud in November's elections, which Suu Kyi's party won in a landslide.

The Nobel laureate -- who has not been seen since she was detained in dawn raids -- has been hit with two charges, one of them for possessing unregistered walkie-talkies.

Her hearing is expected on March 1.