Belgium is on high alert after a major anti-terror raid in which two suspected Islamist militants were killed.
The suspects were shot dead in the eastern town of Verviers after they opened fire on police with automatic weapons on Thursday evening.
Officials say they had returned from Syria and planned imminent attacks on police targets. Another suspect was wounded before being arrested.
Searches were also carried out overnight in the Brussels area.
Speaking after Thursday’s raid in Verviers, near the German border, Prosecutor Eric Van Der Sypt said the terror threat level had been raised to three – the second highest.
Referring to the raid itself, 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.”
After the operation, four Kalashnikovs, bomb-making equipment and police clothing were found, according to local media. Security forces remain in the Verviers area.
Police are expected to provide more details at a briefing on Friday.
Anti-terror raids also took place late on Thursday in the capital Brussels and surrounding towns, including Sint-Jans-Molenbeek, Anderlecht and Schaerbeek.
Earlier that day, two suspected Islamists were arrested in the Brussels suburb of Zaventem, Belgian media reported.
Belgian officials say more than 300 people have left Belgium to fight with Islamic militant groups in Syria and Iraq.
Belgian journalist Mark Eeckhaut told the BBC the suspects in Verviers had wanted to attack a police station and cause a large number of casualties.
Eyewitnesses reported hearing heavy gunfire for several minutes and at least three explosions.
Marylou Fletcher, one of the witnesses, told the BBC: “We were going back from shopping and saw the police cars. We thought there was an accident then we heard something blowing up. There were a lot of gunshots.
“My children cried. They are just terrified.”
The area around the train station remains sealed off.
Belgian Prime Minister Charles Michel said the security operation “shows the government’s determination to fight those who want to spread terror”, his spokesman said.
The incident comes a week after attacks in neighbouring France that killed 17 people. Belgian media has reported that some of the weapons used in those attacks were bought in Brussels.
However, Mr Van Der Sypt said no weapons link with the killings in France had been established.
But there are fears that the suspects captured or killed in this operation could have been inspired by the killings in France to accelerate their own plans, the BBC’s Chris Morris in Verviers says.
The attacks in and around Paris – on satirical newspaper Charlie Hebdo, a kosher market and police – have heightened security fears in several European countries.
In May last year, four people were killed inside the Jewish museum in Brussels. A Frenchman of Algerian descent is in custody in Belgium over the attack.