At least 17 people were killed when Myanmar security forces fired on pro-democracy protesters Wednesday as multiple rallies across the country descended into chaos.

Myanmar has been in uproar since February 1 when the military launched a coup and detained civilian leader Aung San Suu Kyi, ending the nation's decade-long experiment with democracy and sparking daily mass protests.

International pressure is mounting: Western powers have repeatedly hit the generals with sanctions, and Britain has called for a United Nations Security Council meeting on Friday.

But the junta has ignored the global condemnation, responding to the uprising with escalating strength, and security services used lethal force on demonstrators again on Wednesday. 

Thirty-four people have now died since the start of the coup, according to an AFP toll.

The military has also hit half a dozen detained journalists with criminal charges that could see them spend up to three years in jail if convicted.

Several cities in Myanmar saw bloody crackdowns on protesters by security forces on Wednesday, with Monywa in the central Sagaing region registering at least seven.

"What we can confirm is seven people have died," said an emergency doctor, who declined to provide his name.

Multiple medics also said they saw two other individuals being dragged away by security forces, though they could not get close enough to confirm if they had died. 

In the outskirts of commercial hub Yangon at least six demonstrators died, according to a rescue worker and local journalist.

Parts of the city were transformed, with protesters using makeshift tyres and barbed wire barricades to block major roads.

Near the famed Sule pagoda intersection, protesters pasted print-outs of junta leader Min Aung Hlaing's face on the ground -- a tactic aimed at slowing down security forces who will avoid standing on the portraits.

Democracy is our cause

Local media in northern Kachin state also reported similar scenes of violence, publishing images of police bearing down on protesters in Hpakant. 

"Some were hit with rubber bullets and some were suffocating because of tear gas," a doctor told AFP, saying his private hospital treated 10 injured.

Two critically wounded people -- one struck in the chest, the other in the neck -- had to be driven to the state capital's hospital about four hours away.

Parts of commercial hub Yangon were transformed, with protesters using makeshift tyres and barbed wire barricades to block major roads.

Near the famed Sule pagoda intersection, protesters pasted print-outs of junta leader Min Aung Hlaing's face on the ground -- a tactic aimed at slowing down security forces who will avoid standing on the portraits.

In San Chaung township, which has been the site of intense clashes in recent days, tear gas and fire extinguisher clouds filled the streets as riot police confronted protesters, while a clash in Yangon's outskirts left at least 19 people injured.

"Some got hit with rubber bullets," an official told AFP. "We had to transfer one man to hospital for an operation because a rubber bullet hit his head."

Sunday remains the bloodiest day since the military takeover, with the UN saying at least 18 protesters were killed across the country.

In Dawei Wednesday, one of four gunshot victims from Sunday was cremated.

Mourners held floral wreaths and portraits of Lwin Lwin Oo, 33, as coffin bearers were flanked by hundreds chanting: "We are united, yes we are... Democracy is our cause."

Journalists charged

Wednesday's violence came on the heels of news that six Myanmar journalists would be charged under a law prohibiting "causing fear, spreading false news, or agitating directly or indirectly a government employee", according to their lawyer Tin Zar Oo. 

Among them is Associated Press photographer Thein Zaw, who was arrested Saturday as he covered an anti-coup demonstration in Yangon, while the other five are from Myanmar Now, Myanmar Photo Agency, 7Day News, Zee Kwet Online news and a freelancer.

The maximum sentence for the offence has been increased from two years to three, following amendments made by the junta last month after it took power. 

According to the Assistance Association for Political Prisoners (AAPP) monitoring group, more than 1,200 people have been arrested since the coup, with about 900 still behind bars or facing charges.

But the real number is likely far higher -- state-run media reported more than 1,300 people were arrested on Sunday alone. On Tuesday, media reported that about 500 have been freed in Yangon. 

Some of Myanmar's regional neighbours have condemned the coup, with Singapore's premier Lee Hsien Loong this week saying the country's return to military rule was "an enormous tragic step".