An American editor of a news site in military-ruled Myanmar was detained on Monday as he attempted to take a flight out of the country, his news organisation said, the fourth foreign journalist held since a coup in February.

Danny Fenster (above), 37, the managing editor of Frontier Myanmar, one of the country's top independent news sites, was detained at the main international gateway in Yangon while preparing to fly to Malaysia, Frontier said on Twitter.

It said he had been transferred to...