BRUSSELS (AFP) - Brussels will remain at the highest possible alert level on Monday (Nov 23), with schools and metros closed over a "serious and imminent" security threat in the wake of the Paris attacks, the Belgian Prime Minister said.
Armed police and troops have been patrolling the near deserted streets of the tense capital all weekend after the government raised the terror alert to the highest level of four in a city of one million that is also home to the Nato and European Union headquarters.
Following a meeting of the national security council on Sunday, Premier Charles Michel said the shutdown of the metro system would be extended and all schools would be closed over concerns that extremists were planning a repeat of the Paris gun and suicide bombing attacks that claimed 130 lives on Nov 13.
"What we fear are similar attacks, with several individuals in several places." He said the rest of the country would remain on security alert level three, meaning an attack is considered possible and the threat credible. "The threat is considered serious and imminent," he told reporters.
He said he was aware the situation was "very difficult for everyone".
"We are doing everything possible to return to normal life," he said, adding that officials would review the situation again on Monday.
The historic Grand Place in central Brussels, usually bustling, was virtually empty at the weekend, with business badly hit in the run-up to Christmas as anxious residents heeded government warnings to stay at home.
Mr Michel made no direct mention of the manhunt under way for several suspects linked to the carnage in Paris, including Salah Abdeslam who is thought to have slipped past French security forces after taking part in the attack, which has been claimed by the Islamic State (IS) group.
With the world on edge over the jihadist threat, US President Barack Obama said the most powerful tool in the fight against IS was to say "that we're not afraid".
He added that he would go ahead with a visit to Paris for UN climate talks in December and called on other countries to show similar resolve.
As well as Mr Obama, French President Francois Hollande is to meet world leaders in coming days including Russian President Vladimir Putin, Germany's Angela Merkel and Britain's David Cameron to discuss the IS threat.
The UN Security Council on Friday authorised nations to "take all necessary measures" to fight jihadist violence after a wave of attacks, including the downing of a Russian aircraft in Egypt with the loss of 224 lives and the storming of a luxury hotel in Mali that left 19 dead.
Mr Putin said the Mali attack, in which six Russians died, showed "terrorism knows no borders" and must be confronted "with the broadest international cooperation". Moscow announced separately it had killed 11 IS-linked fighters in its volatile North Caucasus region.
In a still jittery Paris meanwhle, French Defence Minister Jean-Yves Le Drian said a chemical or biological attack "was among the risks" faced but that all possible precautions had been taken.
He added that French jets would be able to launch air strikes on IS targets in Syria and Iraq from the Charles de Gaulle aircraft carrier in the eastern Mediterranean starting on Monday.
Belgium and its capital are no strangers to Islamist violence.
Four people were shot dead at the Brussels Jewish museum last year, and in January security forces killed two suspects linked to the Charlie Hebdo killings in Paris.
In Turkey, police arrested a Belgian of Moroccan origin, Ahmet Dahmani, 26, who reportedly scouted targets for the Paris attacks, in which gunmen and suicide bombers hit bars, restaurants, a rock concert and the national football stadium.
The suspected ringleader of those attacks, Abdelhamid Abaaoud, died in a massive police raid in Paris on Wednesday along with his cousin Hasna Aitboulahcen, reportedly a one-time party girl who turned to radical Islam about six months ago.
Abaaoud was a notorious Belgian jihadist thought to be fighting in Syria, and his presence in Europe has raised troubling questions about a Europe-wide breakdown in intelligence and border security.
Questions remain too over the role played by Abdeslam - who used to run a bar with his brother Brahim in Brussels.
Brahim died when he blew himself up outside a bar in Paris.
A third brother, Mohamed Abdeslam, told RTBF television Sunday he believed Salah had changed his mind at the last moment and had not gone through with his attack.
Mr Mohamed Abdeslam said the family wanted Salah to give himself up.
"That way he can give us the answers we seek, our family and the families of the victims," he said.
"We would rather see Salah in prison than in the cemetery."