The United States on Friday denounced an 11-year sentence handed to US journalist Danny Fenster by Myanmar's military regime and demanded his release.

"We strongly condemn the regime's sentencing of Danny Fenster. The ruling today represents an unjust conviction of an innocent person," a State Department spokesperson said.

"We are closely monitoring Danny's situation and will continue to work for his immediate release," he said.

"Journalism is not a crime. Free and independent media is indispensable to building prosperous, resilient and free societies. "

Rights groups have spoken out about the excessive sentencing.

“We regret today’s harsh ruling against journalist Danny Fenster, call for his immediate and unconditional release, and for all charges pending against him to be dropped,” said Shawn Crispin, CPJ’s senior Southeast Asia representative on Friday. “Myanmar must stop jailing journalists for merely doing their jobs of reporting the news.”

International Crisis Group's Myanmar senior advisor Richard Horsey described the sentence as "outrageous".

"It sends a message not only to international journalists... but also Myanmar journalists that reporting factually on the situation is liable to get them many, many years in prison," he said, noting US diplomats were working to get Fenster released.

"It will be resolved through diplomatic channels and hopefully very quickly," he said, "But obviously this sentence is a big setback to US efforts."

Human Rights Watch (HRW) said the long prison sentence against a journalist was a travesty of justice by a kangaroo court operating at the beck and call of the Myanmar military junta.

“Danny Fenster has done nothing that should be considered a crime. This bogus conviction should be quashed, and Fenster should be immediately released and permitted to leave the country if that is what he wants,” said HRW Deputy Asia Director Phil Robertson.

“The junta’s rationale for this outrageous, rights abusing sentence is first to shock and intimidate all remaining Burmese journalists inside Myanmar by punishing a foreign journalist this way. The message is that ‘if we can do this to a foreigner, imagine what we will do to you.’ The second message is more strategic, focused on sending a message to the US that the Tatmadaw’s generals don't appreciate being hit with economic sanctions and can bite back with hostage diplomacy,” Robertson said in a press release.

“Danny Fenster must be freed as soon as possible, as the first step in a campaign of greater pressure to compel an immediate halt to the junta’s repression of media freedom, and ongoing arrests of journalists. Journalism is not a crime, and reporters shouldn't be arrested, prosecuted and jailed for just reporting what’s actually happening in Myanmar. We stand in solidarity with Danny Fenster, and demand that he and the many Burmese journalists still behind bars should be urgently freed,” he said.

Ming Yu Hah, Amnesty International's deputy regional director for campaigns, deemed the ruling "a reprehensible outcome in a case that has been deeply flawed from the start."

The United Nations rights chief expressed concern about the journalists imprisoned in Myanmar.

"Myanmar has quickly reverted to an environment of information control, censorship and propaganda seen under military regimes in the past," UN rights chief Michelle Bachelet said in a statement. "I urge the military authorities to immediately release all journalists being detained in relation to their work."

More than 100 journalists have been arrested since the putsch, according to Reporting ASEAN, a monitoring group. It says 31 are still in detention.

Fenster, who had been working for local outlet Frontier Myanmar for around a year, was arrested in May as he tried to leave the country to see his family.

He was sentenced to 11 years for incitement, unlawful association and breaching visa rules, his lawyer Than Zaw Aung said.

His client had not decided whether he would appeal, he added.

Fenster, who has been held in Yangon's Insein prison since he was detained, also faces extra charges of sedition and terrorism, which could see him jailed for life.

"Everyone at Frontier is disappointed and frustrated at this decision," Frontier Myanmar, his employer, said in a statement. "We just want to see Danny released as soon as possible so he can go home to his family."

AFP, additional reporting Mizzima