Belgian police have killed two men in a fierce gunfight - foiling a major and imminent terror attack in the country, according to authorities.
As police closed in near a train station, the suspects opened fire with automatic weapons and there was an intense shootout for several minutes before the pair were killed, said a prosecutor.
Eric Van Der Sypt also said no officers or civilians were hurt in the raid on an upper level of a building.
He said: "The suspects immediately and for several minutes opened fire with military weaponry and handguns on the special units of the federal police before they were neutralised."
He said police buildings were the target and an attack had been expected in hours or days.
One person, who was reportedly badly injured in the raid, was arrested.
Belgium's public broadcaster RTBF said the operation was on an apartment above a bakery and explosions and gunfire were heard near the train station.
The website of La Meuse newspaper quoted an unidentified police officer as saying: "We've averted a Belgian Charlie Hebdo."
The French satirical magazine was attacked last week by brothers Said and Cherif Kouachi who killed 12 people.
But Mr Van Der Sypt said there was, for the time being, no direct connection to the Paris attacks.
He said more anti-terrorist raids were taking place in the Brussels region and Verviers, adding that Belgium's terror alert level was raised to its second-highest level.
Video posted online of what appeared to be the deadly operation showed a dark view of a building amid blasts, gunshots and sirens, and a fire with smoke billowing up.
One resident told RTL: "I heard the first explosion and then several shots. I cannot say more at this time. I dare not go down to take a look."
Meanwhile, Prime Minister David Cameron, speaking in the US, said: "It looks like yet another indication of the huge risk we face from Islamist extremist terror in Europe.
"It just underlines that our intelligence and security agencies need to work pretty closely, we need to remain vigilant and we need to take all the steps we can to beat this evil."
The operation was one of several being conducted against people believed to have returned to Belgium after taking part in the Syrian civil war.
It has the highest number of citizens per head of population in Europe who have fought for the Syrian rebels, research says.
Police were reportedly hunting a man who witnesses said had brandished a weapon and shouted religious slogans in Arabic at a Brussels metro station.
Earlier, Belgian authorities arrested a man suspected of supplying the gunmen who killed 17 people in Paris, as funerals for the victims of the Charlie Hebdo attacks continued.
Police in Charleroi are holding the suspect on suspicion of arms dealing after he handed himself in to police in the city on Tuesday.
He told officers he had been in touch with Amedy Coulibaly, the militant who took hostages in a Jewish supermarket in the French capital and was later killed by security forces.
According to reports, the man said he had conned Coulibaly in a car sale.
But police later found evidence the pair were negotiating the sale of bullets for a 7.62mm caliber firearm - the type needed for the Tokarev pistol Coulibaly used in his attack on the supermarket in Paris that left four hostages dead.