Postimees' front page and website masthead turned red and white on Thursday to show support for Belarusians.
The historic red and white flag is carried by protestors demanding democracy and freedom on the streets of Minsk instead of the red and green national flag.
"At this time it would be wrong to give way to the bullying of a cornered dictator, particularly in a free world where the freedom of speech and opinion are protected. The decision of Latvia to replace the Belarusian state flag with the white-red-white flag at the ice hockey world championship is also a good example," Thursday's editorial of Postimees reads.
"Postimees' message to Alexander Lukashenko and his autocratic regime is unambiguous - we are standing up for democracy and free media in Belarus! May knowing this encourage this country's nation and journalism, which are made to live in fear," it said.
On Sunday, Ryanair FR4978 flight had been flying in Belarusian airspace but was forced to turn back before crossing the Lithuanian border and was escorted to Minsk Aiport by Belarusian military aircraft. It was initially reported a bomb threat had been made but the Belarusian authorities found no trace of explosives when the plane was searched.
Belarusian opposition activist and blogger Roman Protasevich, 26, was onboard the flight with 171 other passengers traveling between Greece and Lithuania and was arrested upon landing in Minsk.
Protasevich fled Belarus in 2019 and was active in reporting on the 2020 presidential election on his Nexta channel on Telegram used by the country's opposition. The Belarusian security service, KGB, has listed him as a terrorist and potentially faces the death pentalty.
In recent weeks the Belarusian authorities have raided independent media outlets. Journalists who covered protests last year have been sent to prison.
Editor: Helen Wright