Paris attacks suspect Salah Abdeslam has been wounded and captured in a huge anti-terror operation in Brussels after four months on the run.
Belgian prime minister Charles Michel confirmed the news at a press conference alongside French president Francois Hollande hours after heavily armed officers stormed a building in the city's Molenbeek district.
He said that two other men were also held in the operation in a part of the Belgian capital some of the Paris attackers, including suspected ringleader Abdelhamid Abaaoud, were from.
Mr Hollande congratulated the Belgian authorities and said moves would start to extradite Abdeslam, who was born in Brussels, back to France.
Mr Hollande said: "I have a special thought for the victims of the attacks on November 13 in Paris, because SA is directly connected to the preparation, organisation and ... the perpetration of these attacks.
"I also think of the families who have been looking forward to these arrests, whether from close range or long distance, who are connected to that abomination."
Belgian migration minister Theo Francken confirmed the arrest earlier on Friday, tweeting: "We've got him".
Mr Michel left the EU-Turkey migrant crisis summit amid reports of the raid.
TV footage showed armed officers descending on the area and gunshots and explosions were reported.
Fire engines and ambulances were seen driving into the gated complex, which remains under armed police guard, and a helicopter hovered overhead.
Members of the public also began to gather at the scene.
Local media said police, who were joined at the scene by the army, appeared to use grenades while eyewitness reports suggested white smoke could be seen coming from a property.
At least ten gunshots were reportedly heard.
The news came after the Belgian authorities said a man shot dead earlier this week was probably an accomplice of Abdeslam.
Fingerprints found at the address where Algerian national Mohamed Belkaid was killed suggest Abdeslam had been there too.
Two men escaped from the apartment during the gunfight with police and one of them is now thought to have been Abdeslam, 26, who fled from Paris after the terror attacks in November which killed 130 people.