Britain on Thursday condemned "bullying" by the Myanmar junta after the country's ambassador to London was ousted in an extraordinary diplomatic coup having called for the release of civilian leader Aung San Suu Kyi.

Diplomats loyal to the Myanmar military authorities seized control of the embassy on Wednesday, leaving ambassador Kyaw Zwar Minn locked out in the street.

The ambassador said the defence attache had taken over the mission in "a kind of coup", two months after the military seized power in Myanmar, and urged the international community to help his country.

Myanmar Protests
The Myanmar military has arrested leading actor, model and heartthrob Paing Takhon for supporting the anti-coup protests Photo: AFP / STR

"Please assist our country and help our country as without international assistance we will not be able to get out of this mess," he told reporters outside the embassy.

Daily protests demanding a return of democracy have rocked the country and brought a brutal response from the armed forces, with almost 600 civilians killed according to a local monitoring group.

Vowing to deprive the military junta of a key moneymaker, the United States on Thursday slapped sanctions on Myanmar's state gem company, Myanmar Gems Enterprise.

Myanmar Embassy in London
Diplomats loyal to Myanmar's junta have seized the country's embassy in London, leaving ambassador Kyaw Zwar Minn locked out in the street Photo: AFP / Niklas HALLE'N

The US is committed to "denying the Burmese military sources of funding, including from key state-owned enterprises throughout Burma," said Andrea Gacki, director of the Treasury Department's Office of Foreign Assets Control, using Myanmar's former name.

The department said it would block all assets and ban any transactions with the company.

The coup has prompted several high-profile diplomatic defections, including the country's ambassador to the United Nations.

Myanmar Protests
Myanmar has been shaken by an anti-coup protest movement since the generals ousted the civilian government of Aung San Suu Kyi Photo: AFP / STR

The junta recalled Kyaw Zwar Minn last month after he issued a statement urging them to release Suu Kyi and deposed civilian President Win Myint.

Myanmar Ambassador to the UK
SOUNDBITE Myanmar Ambassador to the United Kingdom Kyaw Zwar Minn says a military attache has 'occupied' the London embassy. Photo: AFPTV / Will EDWARDS

British foreign minister Dominic Raab tweeted his support for the ambassador, who spent the night in his car outside the embassy.

"We condemn the bullying actions of the Myanmar military regime in London yesterday, and I pay tribute to Kyaw Zwar Minn for his courage," Raab wrote.

"The UK continues to call for an end to the coup and the appalling violence, and a swift restoration of democracy."

Myanmar human rights abuses
Graphic on rights abuses by the military junta since the February 1 coup, as listed by a group representing Myanmar's ousted clivilian government Photo: AFP / John SAEKI

UK sources said the Myanmar authorities had given official notice of Kyaw Zwar Minn's termination as ambassador, and in line with diplomatic policy the government had no choice but to accept it.

The defence attache has installed deputy ambassador Chit Win as charge d'affaires.

Myanmar's military spokesman Zaw Min Tun confirmed the country's foreign affairs ministry had been in touch with their UK counterparts in London over the incident.

The Myanmar military has arrested leading actor, model and heartthrob Paing Takhon for supporting the anti-coup protests Photo: AFP / STR

"We have sent an official appointment letter already for Chit Win as the chief of mission there. They have accepted," he told AFP, adding the ambassador was required to return home.

Myanmar's security forces have struggled to quell protests and a civil disobedience movement aimed at overturning the February 1 military coup.

They have used rubber bullets and live rounds to break up rallies and used night raids to arrest suspected dissidents.

The Assistance Association for Political Prisoners (AAPP) says at least 598 civilians have been killed and nearly 2,900 detained.

There were at least six further deaths on Thursday after residents in Taze in the northwestern Sagaing region tried to block the army from reaching the town.

"Our people used (homemade) guns and attacked them. But they used real bullets and shot us," one witness told AFP.

"Six people were killed from our town," the witness said, adding that five others were wounded.

Local media said 11 people were killed.

As part of its efforts to suppress the movement, the junta has issued a wanted notice for about 140 celebrities accused of fanning the protests by lending their support.

On Thursday, the military arrested leading actor, model and heartthrob Paing Takhon in a dawn raid at his mother's home in Yangon.

The 24-year-old -- a star in both Myanmar and neighbouring Thailand -- has been active in the protest movement both in person at rallies and through his massive social media following.

In February, he posted pictures of himself in a white tracksuit with a megaphone, hard hat and a white fluffy dog strapped to his chest at a protest.

International powers have voiced anger and dismay at the junta's brutal approach, but the UN Security Council has stopped short of considering sanctions, with both China and Russia against the move.

Junta chief General Min Aung Hlaing accused the protesters of wanting to "destroy the country" and said only 248 protesters had been killed, along with 16 police officers.

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