Belgian police on Thursday were combing a national park for a soldier suspected of extreme-right views who went missing after stealing arms from a military base and threatening public figures.

Some 300 police and army personnel were deployed on the hunt for Jurgen Conings, 46, after his abandoned vehicle was found in the area near the Dutch border on Wednesday evening with four rocket launchers inside.

-The search continued throughout the night- federal prosecutor spokesman Eric Van Duyse told AFP.

Van Duyse warned that Conings likely remained armed and dangerous after he was suspected of stealing weapons from a military base where he worked as an instructor.

The manhunt dominated newspaper headlines in the country, with one tabloid labelling him the "Belgian Rambo" after the 1980s action film staring Sylvester Stallone.

Authorities earlier said that they had discovered a letter left behind by the fugitive that included threats to the state and public figures.

Among the people Conings has threatened is Marc Van Ranst, a leading virologist who has become a target for conspiracy theorists, Covid-sceptics and the Flemish far-right in Belgium during the coronavirus crisis.

Conings, whose Twitter profile describes himself as a "Belgian Air Force soldier who likes fitness, body building and boxing", already figured on a list of extremists monitored by Belgium's anti-terrorist agency.

He was one of around 30 Belgian military personnel with known extremist sympathies, officials said, but he remained on active duty, training Belgian troops ahead of deployment on overseas missions.

Prime Minister Alexander de Croo said it was "unacceptable" that the fugitive had been allowed to access the weapons at the military facility, and Defence Minister Ludivine Dedonder said an inquiry would be launched.