Belgian authorities charge fourth suspect with Paris attacks

A Belgian anti-terrorism judge on Monday charged a suspect with involvement in the Paris attacks, the federal prosecutor's office said, the fourth person to face charges in Belgium over the 13 November atrocities.

The suspect was arrested in a series of police raids in Belgium on Sunday night along with 15 others who were all released without charge, as authorities warned of a Paris-style plot facing Brussels which was on security lockdown on Monday.

Prime Minister Charles Michel announced on Monday night that schools and the metro would reoped in the city on Wednesday after earlier warning that the city faced a "serious and imminent" threat of attacks similar to those that killed 130 people in France.

Meanwhile in the southern Paris suburb of Montrough, a street cleaner reportedly found an explosive belt without detonator in a pile of rubble, French police told the Associated Press. Police are analysing the belt to see if it may be linked to the Paris attacks.

In Brussels, the unnamed fourth suspect was charged late Monday with "participating in activities of a terrorist group and with terrorist attack (Paris)," the prosecutor's office said in a statement. 

"After thorough interrogation by the federal judicial police, the remaining 15 persons were released by the investigating judge."

Mohammed Amri, 27, and Hamza Attou, 20, were charged last Monday on suspicion of helping alleged Paris attacker Salah Abdeslam with escaping to Brussels after the attacks carnage in which 130 people died.

A third person who has not been publicly named was also charged with involvement in the Paris attacks on Friday and is reported to have helped Salah when he was dropped off in the Belgian capital.

The charges come after more than 20 raids around the country over Sunday night and into Monday. Key suspect Abdeslam, however, slipped through the net.

"Salah Abdeslam was not caught during the raids," federal prosecutor spokesman Eric Van Der Sypt told a press conference just after midnight, meaning Europe's most wanted man remains at large.

Abdeslam's elder brother Brahim blew himself up outside a Paris bar in the 13 November attacks.

Armed officers and troops have been patrolling the nearly deserted streets of the tense Belgian capital all weekend after the government raised the terror alert to the highest level of four in the city.

The European Union and NATO, which are based in Brussels, both said they would increase security and urged non-essential staff to work from home on Monday.

'Serious and imminent'

"What we fear are similar attacks, with several individuals in several places," Michel told reporters earlier on Monday.

"The threat is considered serious and imminent," he said, adding that the rest of the country, including Brussels airport, would remain on security alert level three, meaning an attack is considered possible and the threat credible.

The historic Grand Place square 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 warnings to stay home.

With a massive manhunt on for several suspects linked to the carnage in Paris, Belgian police urged the media and social media not to show live footage of the police operations taking place Sunday evening.

Many Belgians responded in light-hearted fashion by tweeting pictures of cats under the hashtag #BrusselsLockdown.

Interior Minister Jan Jambon earlier said the authorities were looking for "several suspects" and not just for Abdeslam, who is thought to have slipped past French security forces after taking part in the Paris attacks, which were claimed by the Islamic State (IS) group.

French police meanwhile released a photo of the third of three men who blew themselves up outside France's national stadium during the rampage, which also targeted the Bataclan concert hall as well as a string of bars and restaurants.

The man in the picture passed through Greece with one of the other suicide bombers, carrying a Syrian passport in the name of Mohammad al-Mahmod, a source close to the investigation said.

Obama 'not afraid'

With the world on edge over the militant 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 December visit to Paris for UN climate talks and called on other countries to show similar resolve.

French President Francois Hollande will embark on a diplomatic offensive in the coming days in a bid to forge a broad anti-IS coalition.

He will host Britain's David Cameron on Monday before meeting Obama in Washington on Tuesday, holding talks with Germany's Angela Merkel in Paris on Wednesday and Russia's Vladimir Putin in Moscow on Thursday.

The UN Security Council on Friday authorised "all necessary measures" to fight militant violence after a wave of deadly 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.

Bataclan band speaks out

Meanwhile, Eagles of Death Metal, the Californian band that was playing at the Bataclan where 89 people were massacred, spoke for the first time since the attacks, with singer Jesse Hughes saying that many fans died trying to protect their friends.

"So many people put themselves in front of people," he said in an excerpt of an interview with Vice.com.

The suspected ringleader of the 13 November attacks, Abdelhamid Abaaoud, died in a massive police raid in Paris on Wednesday.

He was a notorious Belgian militant 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 Belgian-born Abdeslam - who used to run a bar with his brother Brahim in Brussels.

A third brother, Mohamed Abdeslam, told Belgian TV on Sunday he believed Salah had at the last moment decided not go through with the attack.

He said the family wanted him to give himself up.

"That way he can give us the answers we seek, our family and the families of the victims," he said.