The military has squeezed the press since taking power in a coup last year, arresting dozens of journalists critical of its crackdown, which has killed more than 1,400 people according to a local monitoring group.

Three Dawei Watch employees were arrested "one after the other" in separate raids in the city of Dawei during the night of January 18 and the early hours of January 19, a source at the outlet told AFP.

Two of the three are journalists, and the third a web designer, said the source, who requested anonymity.

"We don't know why" the three were arrested, they said, adding that all three were being held at a police station in the southern city and that their families had been allowed to send them food, clothes and medicine.

Local media also reported the arrests.

Since the coup, 115 journalists have been arrested, according to local monitoring group Reporting ASEAN, with 44 still in prison. One has died in custody, according to the group.

Only China jailed more reporters than Myanmar last year, according to the Committee to Protect Journalists.

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