A US editor of a Myanmar-based news outlet was detained by authorities in Yangon on May 24 as he attempted to board a flight out of the coup-hit country, his employers said.

US citizen and managing editor of Frontier Myanmar Danny Fenster was detained at Yangon International Airport, the outlet said in a statement on its verified Twitter account.

The US Department of State said it was “aware of reports” of the arrest.

“We take seriously our responsibility to assist US citizens abroad, and are monitoring the situation,” a spokesman said, while declining to provide further details for privacy reasons.

Myanmar has been in uproar since the military seized power in a February 1 coup, with near-daily protests and a nationwide civil disobedience movement.

More than 800 people have been killed by the military, according to a local monitoring group.

The press has been caught in the crackdown as the junta tries to tighten control over the flow of information, throttling internet access and revoking the licences of local media outlets.

“We do not know why Danny was detained and have not been able to contact him since this morning. We are concerned for his wellbeing and call for his immediate release,” Frontier said in a tweet.

“Our priorities right now are to make sure he is safe and to provide him with whatever assistance he needs.”

Fenster, 37, had been working for the outlet for around a year and was heading home to see his family, Frontier’s chief editor Thomas Kean told AFP.

The outlet had learned at around 10am that Fenster had not been allowed to board his flight from Yangon, he added.

In a message shared with AFP, Fenster’s brother Bryan said the family was “stunned and extremely confused” by the detention.

“We’ve been assured that there is no concern for his safety but no doubt we are very worried,” he said.

At least 34 journalists and photographers remain in custody across Myanmar, according to monitoring group Reporting ASEAN.