A military court in Myanmar has jailed a journalist for life and sentenced another to 20 years in prison after convicting them under a counterterrorism law, their editor said on Thursday.

Myo Myint Oo and Aung San Oo, who work for the independent online news service Dawei Watch, were sentenced after being denied the right to legal defence and not being allowed to speak in court, editor Ko Kyaw told AFP.

Since overthrowing Aung San Suu Kyi's civilian government in February 2021, Myanmar's military junta has waged a sweeping and bloody campaign against dissent, including targeting independent journalists.

The two journalists were arrested at their homes in the coastal town of Myeik, about 560 kilometres (350 miles) south of Yangon on December 11.

Myo Mynit Oo, 40, was handed a life sentence on May 15, while Aung San Oo, 49, was handed a 20-year jail term on February 16.

They were "violently interrogated" for four days in a detention centre before being transferred to the Myeik Prison, a statement from Dawei Watch said.

Ko Kyaw said he learned about the sentences earlier this year but delayed announcing them for the security of the journalists' families, without providing further details.

The court has not given a detailed explanation of the the case, Ko Kyaw said.

Myanmar is now one of the world's biggest jailers of journalists with 62 detained, second only to China, according to the Paris-based campaign group Reporters Without Borders (RSF).

Myanmar now ranks 171 out of 180 in RSF's 2024 World Press Freedom Index.

Last September a Myanmar journalist was jailed for 20 years after being indicted on several charges, including breaching a natural disaster law and a telecommunications law while covering the aftermath of a deadly cyclone.

Several foreign journalists have been detained, including US citizen Danny Fenster, who was jailed for 11 years in 2021, before being pardoned and released days later.