Belgian authorities have charged two men with terrorist offences after raids overnight, the federal prosecutor's office said Saturday amid reports of a planned attack on a Euro 2016 fanzone.
"Two persons... were taken for questioning and arrested by the investigating judge," a statement said.
"They are charged, as perpetrator or co-perpetrator, for participation (in) the activities of a terrorist group."
It said several houses were raided overnight in Verviers, in eastern Belgium, and in Tournai, close to the border with France.
No weapons or explosives were found, it said, adding that no further information would be given as the investigation continued.
A spokesman said earlier one man was detained in each town.
Belgium remains on high alert after attacks in March claimed by the Islamic State (IS) group on Brussels airport and on the city's busy metro system left 32 people dead.
Several of those involved were directly linked to the Paris November attacks, planned in Brussels and also claimed by IS, which killed 130 people.
RTL news service, citing unnamed sources, said on its website the man detained in Verviers was planning an attack on fans watching Belgium's next Euro 2016 game against Hungary on Sunday.
Last Saturday, Belgium charged three men with "attempted terrorist murder" after massive anti-terror raids linked to a reported threat to fans during a Euro 2016 game.
At the time, prosecutors said they were responding to the need for "an immediate intervention".
Belgium police killed two IS militants in a raid in Verviers in January 2015 who were later found to be linked to the cells involved in both the Brussels and Paris attacks.
Euro 2016 host France meanwhile is on maximum alert.