Danny Fenster, looking gaunt after his six-month imprisonment, said he was held for no reason but not mistreated by the Myanmar authorities.

The 37-year-old American -- who was handed an 11-year sentence last week for incitement, unlawful association and breaching visa rules -- was freed one day before he was to face terror and sedition charges that could have seen him jailed for life.

"I was arrested and held in captivity for no reason... but physically I was healthy," he told journalists after arriving in the Qatari capital Doha. "I wasn't starved or beaten."

Myanmar's military has squeezed the press since taking power in a February coup, arresting dozens of journalists critical of its crackdown on dissent, which has killed more than 1,200 people according to a local monitoring group.

Fenster had been working at Frontier Myanmar, a local outlet in the Southeast Asian country, for around a year and was arrested as he headed home to see his family in May.

"I'm feeling all right physically. It's just the same privations that come with any form of incarceration. You're just going a little stir-crazy," Fenster said, who will fly onwards to the United States from Doha.

"The longer it drags on, the more worried you become that it's never going to end. So that's the biggest concern, just staying sane through that."

- 'So happy' -

On Monday, Fenster was pardoned and released on "humanitarian grounds" the junta said, ending 176 days spent in a colonial-era prison where many of Myanmar's most famous dissidents have been held.

His release was secured following "face-to-face negotiations" between former US diplomat Bill Richardson and junta chief Min Aung Hlaing, Richardson's organisation said in a statement.

Fenster's father Buddy expressed relief after speaking with his son on the phone, saying there was "nothing harder on a parent" than knowing a child is in distress and being unable to help.

"He has been sleeping on a wooden pallet for close to six months. And he said, 'The plane's got a bed in it' and I said, you know, 'Danny, take a rest, man, just stretch out on that thing.' I'm just so happy to hear that," he said.

The junta said two Japanese envoys, Hideo Watanabe and Yohei Sasakawa, had been involved in the negotiations to release Fenster, without providing details.

"It's wonderful news for all of his friends and family," his colleague at Frontier Myanmar, Andrew Nachemson, told AFP.

"But of course he never should have spent six months in jail... and all the local journalists who remain imprisoned should also be released immediately."

- 'Hostage' -

The United States welcomed his release, saying he had been "wrongfully detained".

"We are glad that Danny will soon be reunited with his family as we continue to call for the release of others who remain unjustly imprisoned in Burma," US Secretary of State Antony Blinken said, using Myanmar's former name.

Richardson visited Myanmar earlier this month on what was described as a "private humanitarian mission."

He said at the time that the US State Department had specifically asked him not to raise Fenster's case during his visit.

Fenster is believed to have contracted Covid-19 during his detention, family members said during a conference call with American journalists in August.

"I doubt there were any concessions" from Washington, International Crisis Group's Myanmar senior advisor Richard Horsey told AFP.

"More likely it was politely explained that keeping US citizens hostage is a bad idea."

Myanmar has been in turmoil since the military seized power in February, ousting Aung San Suu Kyi's elected civilian government.

More than 10,000 people have been arrested by security forces in a crackdown on dissent, according to a local monitoring group.

Media outlets have also been under pressure as the junta tries to tighten control over the flow of information, throttling internet access and revoking the licences of local outlets.

More than 100 journalists have been arrested since the putsch, according to Reporting ASEAN, a monitoring group. It says at least 30 are still in detention.