Belgium has arrested 16 people in 22 raids on Sunday night even as the authorities maintained their highest terror alert in the capital, Brussels for a third straight day.
However, Paris fugitive Salah Abdeslam was not among those arrested.
Federal prosecutor Eric Van Der Sypt said 19 raids were carried out in Molenbeek and other boroughs of Bussels and three raids were carried out in other cities.
"We have to stress that no firearms or explosives were discovered ... during the raids," Van Der Sypt said." Certain elements in the investigation made yesterday's intervention necessary. The investigation will in any case be relentlessly continued."
Sunday's operation, the biggest in the Belgian capital since the Paris attack, began shortly after a government meeting on the crisis.
Belgian officials decided on Sunday to extend a partial lockdown of the city through Monday, keeping the capital on its maximum terrorism alert level. Besides the metro, schools will also be shut.
Prime Minister Charles Michel said that authorities had received "additional information" on Sunday that had led to his decision to enforce the extraordinary measures.
"We fear an attack like the attack in Paris," he said in a news conference. "Meaning several individuals conducting an attack in Brussels, possibly in several places at the same time."
According to a Washington Post report, the highly unusual measures in the Belgian capital underscore the fear gripping Europe a little more than a week after the coordinated assaults in Paris, which killed 130 people and injured more than 350 and brought into focus the Islamic State's ability to strike the West directly.
Belgian officials are casting a wide net for those involved in the Paris attacks and others who may be preparing to strike in Belgium. A primary target is Salah Abdeslam, a 26-year-old French national who is the subject of a manhunt across Europe. Abdeslam, who was identified as one of at least nine suspected attackers, is believed to have made his way to Belgium after the attacks.
A former French intelligence official close to the investigations told the New York Times that the Belgians were looking for eight to 10 people who were heavily armed with weapons and explosives, in addition to Abdeslam.
With the country's threat level at 4 -- the highest possible -- the United States Embassy in Brussels continued to advise citizens to 'remain at home' and avoid public gatherings. The authorities announced that schools and subways in Brussels would remain closed on Monday.
A railway station under the headquarters of the European Union's executive branch remained sealed off on Sunday, and all traffic on the Brussels metro system was suspended. Soldiers with automatic weapons patrolled malls. Several big stores stayed closed. A huge Sunday market near the Brussels-South railway station that usually draws as many as 50,000 shoppers was canceled.
Image: A Belgian soldier stands guard outside a cafe near Brussels' Grand Place. Photograph: Yves Herman/Reuters
