Police have arrested 12 people in a bid to foil a suspected terror attack on football supporters in Brussels watching Belgium’s Euro 2016 game against Ireland later today.

Officers made the arrests and raided dozens of homes and garages across Belgium overnight during a major police operation.

Flemish public broadcaster VTM said the people arrested overnight were suspected of planning an attack in Brussels this weekend during one of Belgium's matches in the Euro tournament.

Belgian police on Wednesday received an anti-terror alert warning that a group of Islamic State fighters recently left Syria en route for Europe planning attacks in Belgium and France, security officials said.

The federal prosecutor's office said in a statement “immediate intervention” had been required.

"In connection with a criminal investigation concerning terrorism 40 persons were taken for questioning. Twelve among them were arrested,” the statement said.

“The investigating judge will decide on their possible detention later today.”

Belgium play Ireland in Bordeax, France, this afternoon, but it is believed terrorists were planning to target fans watching the game in Brussels.

No firearms or explosives were found in the raids carried out in 16 municipalities, mostly in and around Brussels.

The operation comes after Islamist suicide bombers killed 32 people in Brussels in March following attacks in Paris in November in which 130 people died.