They invaded the Place de la Bourse as people paid tribute at a makeshift memorial for victims of last Tuesday's deadly attacks.

Riot police intervened to try to restore order after the group confronted Muslim women in the crowds, made Nazi salutes and chanted.

The attacks at Brussels airport and on the metro killed 28 people.

A "march against fear" planned for Sunday was called off after the authorities said it would strain police resources for the investigation.

Belgian police also carried out 13 new raids and took more people in for questioning on Sunday as part of investigations into the attacks.

A man already in Belgian custody was reported to have been charged in connection with a foiled attack in the Paris region.

The BBC's Anna Holligan in Brussels says the group involved actually call themselves Casuals against Terrorism - not Fascists against Terrorism as earlier reported.

Some of the hundreds-strong group wore balaclavas and anonymous masks. Many wore black clothing. Some reports described them as football hooligans.

One of them, called Andres, told AFP news agency: "We are football hooligans, we don't have anything to do with politics."

"We are here for the victims and to pay our respects," he said.

One witness, Adam Liston, told the BBC there had been a "really positive atmosphere" in the square, as people crowded round the floral tributes in solidarity with the victims.

"Then a bunch of skinheads just turned up, marched into the square, and started a major confrontation with the peace protesters. They got in the face of the protesters and police. They set off flares and chanted and it was getting quite ugly," he said.

He added that although it had been "pretty non-violent", it looked like it "could have kicked off".

A provisional inspection of the terminal found the main building was stable.

Meanwhile, a Belgian news agency has reported that prosecutors charged a second man in connection with a foiled attack in the Paris region.

However, prosecutors were not available for direct confirmation.

Several people have been arrested on terrorism charges in Belgium, France, Germany and Italy since the attack in Brussels on 22 March, which left 28 people dead. A previous death toll of 31 counted the three suicide bombers.

The latest arrest was linked to a raid in Argenteuil, near Paris, on Thursday. French police said an attack was in an "advanced stage" of preparation.

The state-owned Belga news agency (in French) quoted prosecutors as saying the man, named as Abderamane A, was charged with involvement in a terrorist group.

They said that Abdeslam, arrested last week in Brussels and initially cooperative, had "exercised his right to silence" and said nothing when interviewed after Tuesday's bombings.

He was seized days before the Brussels attacks, in which 31 people died.

Twelve people were arrested on Thursday and Friday in three countries.

Six were detained in Belgium on Thursday and three on Friday, though several were later released.

Two were held in Germany and one in France, as a plot said to be in its advanced stages was foiled.

Meanwhile Belgian officials named the second suicide bomber in Tuesday's attack at Brussels airport as Najim Laachraoui, and said that his DNA was also found at sites of the November Paris attacks.

So-called Islamic State (IS) has said it carried out both the Brussels attacks, and the ones in Paris in November.

On Friday it released a video about the Brussels attacks, presenting them as retribution for coalition attacks against IS territory in Iraq and Syria.

Why have jihadists targeted Belgium?

Why Brussels warning signs were missed

From Paris to Brussels: Why the attacks are linked

What we know so far

Victims and survivors

Abdeslam was arrested on 18 March in a dramatic operation in central Brussels after apparently hiding in the city for more than four months.

Describing Abdeslam's interrogation since his arrest, the prosecutor's office said he was not interviewed that day as he was receiving hospital treatment - he was wounded in the leg during his arrest.

His first interview was at 08:00 (07:00 GMT) the following day, when investigators went through the main points of the Paris inquiry.

Two interviews with the investigating judge followed, the second of which related to a European arrest warrant issued against him.

On this occasion Abdeslam exercised his right to silence.

He was interviewed again on 22 March immediately after the Brussels attacks and "declined to make any statement at all", the statement said.

Belgian Justice Minister Koen Geens confirmed in parliament that Abdeslam "no longer wants to talk since the attacks".

Earlier on Friday, the prosecutor's office announced nine arrests, including three in the Forest, St Gilles and Schaerbeek districts of Brussels.

In the most recent raid, a man carrying a backpack was shot in Schaerbeek district after refusing to obey police orders, media say. Controlled explosions were carried out.

An area near Meiser square was sealed off by heavily armed police and military vehicles.

A witness quoted by local media said the man had taken a woman and child hostage. He released the child and was shot despite trying to use the woman as a shield.

Schaerbeek mayor Bernard Clerfayt said a man had been arrested and shot in the leg.

The raids came as US Secretary of State John Kerry visited Brussels to express condolences and solidarity.

The Western alliance would continue its fight to destroy IS, Mr Kerry said.

More details of those killed in the Brussels attacks have been released. Nationals of 40 countries were caught up in the attacks.

Among the deaths confirmed so far:

Twenty people died in a suicide bombing in Maelbeek metro station, and another 11 in blasts at Zaventem airport.

The man, carrying a backpack, was shot in Schaerbeek district after refusing to obey police orders, media say. Explosions were also heard.

Ten other suspects have been held in Belgium, Germany and France.

Police are trying to prevent further attacks after Tuesday's Brussels bombings.

An investigation is continuing into the bombings, which killed 31 people and have been linked to November's Paris attacks.

The Belgian prosecutor has named another of the suicide bombers at Brussels airport as Najim Laachraoui.

So-called Islamic State (IS) has said it carried out both sets of attacks.

An area near Schaerbeek's Meiser square was sealed off by heavily armed police and military vehicles on Friday.

At least three explosions were reported. Bomb disposal personnel and robots were at the scene.

The operation is now said to have finished.

Schaerbeek mayor Bernard Clerfayt said a man had been arrested and shot in the leg.

Eyewitnesses reported seeing a man who had emerged from an underpass armed with a machine gun being shot in the legs by police.

A local resident, named as Marios, also described gunfire.

"I heard two very loud shots," he told the BBC.

"Immediately within seconds police arrived... The streets were evacuated..."

Schaerbeek is one of the districts where arrests were carried out on Thursday. French police sources say the latest raid was also linked to Thursday evening's operation in a Paris suburb during which another attack was apparently foiled.

US Secretary of State John Kerry, visiting Brussels, said that IS would be destroyed.

The Western alliance would continue its fight to destroy IS, Mr Kerry said.

"We will not be intimidated. We will not be deterred."

Why have jihadists targeted Belgium?

Why Brussels warning signs were missed

From Paris to Brussels: Why the attacks are linked

What we know so far

Victims and survivors

Details of further arrests have been emerging:

More details of those killed in the Brussels attacks have been released. Nationals of 40 countries were caught up in the attacks.

Among the deaths confirmed so far:

The Brussels bombings continue to have political repercussions, with questions surrounding the issue of whether more could have been done to prevent them.

Turkey has said it arrested and deported one of the bombers, Brahim el-Bakraoui last June, warning Belgium he was a "foreign fighter" - but the message was "ignored". The Dutch authorities had also been alerted, Ankara said.

Bakraoui is one of three men who carried out the bombings at Brussels airport, killing 11 people.

The Belgian interior and justice ministers said they had offered their resignations but the prime minister refused to accept them.

The other two airport attackers have not yet been identified. Bakraoui's brother, Khalid, struck at Maelbeek metro station, where 20 people died.

There are reports of a second suspect being sought for that attack. One source told AFP news agency that a man with a large bag had been seen beside Khalid el-Bakraoui on surveillance footage at the metro station.

Meanwhile, the Flemish-language public broadcaster VRT reported that investigators were working on the assumption that the cell had been planning a far bigger attack, involving Paris-style shootings as well as suicide bombings.

Links have also emerged with Salah Abdeslam, a suspect in the Paris attacks.

Abdeslam was arrested and wounded in a police raid on a flat in Brussels last Friday - four days before the attacks in the Belgian capital.

Investigators say Khalid el-Bakraoui used a false name to rent the same flat.