A man has rammed his car into the gates of a military barracks near the Belgian city of Namur and later been arrested - but there's no indication of a terror motive, a prosecutor said.
The suspect, born in the French-speaking city of Namur in 1983, "did not figure on terror watch lists" and was "practically unknown" to law-enforcement authorities, prosecutor Vincent Macq told a news briefing.
No casualties were reported in Monday's attack, which immediately rang alarm bells in a country on high alert after a wave of violence by Islamic State-affiliated jihadists, including a deadly attack on a Jewish museum in Brussels in 2014.
"The likelihood that this was an isolated incident, even the act of an mentally impaired individual, cannot be excluded," prosecutor Macq said.
The suspect was arrested hours after fleeing on foot from the Flawinne military barracks where guards fired warning shots at his dark coloured Ford Focus, which he abandoned in a muddy field nearby.
Terrorism "is not the main line of inquiry," Macq said, adding that in 2010 the man had been a candidate to join the military.
There were no explosives in the car, contrary to earlier reports, said Macq.
His only weapon "was his car", he added.
The Flawinne military base, eight kilometres from downtown Namur, is home to Belgium's Second Commando Battalion of 650 soldiers, most of whom are currently taking part in a NATO exercise in Spain.
Only about 50 soldiers were in the facility at the time of the incident.
The prosecutor said the perpetrator was "partly masked" in the attack, and was faced with "a dozen warning shots" by entry guards as he sped towards them.
The incident stirred memories of recent deadly attacks, including the killing of four people at the Jewish museum in central Brussels in 2014 by a jihadist gunman.
In January, the security forces killed two suspected jihadist fighters in Verviers, eastern Belgium, who they claimed were planning imminent attacks on police.