The arrest of Paris attacks suspect Mohamed Abrini in raids linked to the deadly Brussels airport and metro bombings highlighted yesterday the links between the Islamic State jihadists behind Belgium and France's worst terror outrages.

Abrini's arrest Friday, along with four other suspects, marks an important step in the investigations into the November 13 onslaught which claimed 130 lives in Paris and the March 22 attacks which left 32 dead in Brussels.

In both, several of the suspects came from the largely immigrant Molenbeek neighbourhood of Brussels, including Abdelhamid Abaaoud, said to have played a key role in Paris, along with Salah Abdeslam who was arrested on March 18 not far from the family home.

Salah's brother Brahim blew himself up in Paris but for unknown reasons he did not follow suit, fleeing back to Brussels immediately afterwards and eluding police for four months despite a massive manhunt.

The Belgian authorities have faced intense criticism over their handling of the attacks as it emerged many of the suspects were known to police for a long time.

Critics say the government has not done enough to prevent radicalisation of Muslim youth in areas such as Molenbeek, with Belgium proportionately the biggest source of foreign fighters going to join IS in Syria.

In a change of tone, La Libre daily carried a cartoon Saturday showing a policeman kicking a man holding a hat into a prison cell under the banner: "They criticise the Belgian police but ... Hats off!"

A police video released Thursday showed a man wearing a hat and light-coloured jacket who was seen with the two airport suicide bombers in the departure hall.

He fled after they blew themselves up and then made his way on foot back into central Brussels, appearing calm and composed before disappearing.

There has been intense speculation Abrini is the "man in the hat" but the federal prosecutor's office said this could not be confirmed.

"Investigators are verifying whether Abrini can be positively identified as being the third person ... the so-called 'man with the hat'," a spokesman said at a late Friday press conference.

The two airport bombers have been identified as Ibrahim El Bakraoui and Najim Laachraoui, believed to be the cell's bomb maker.

Ibrahim's brother Khalid blew himself up at Maalbeek metro station not far from the European Union quarter in Brussels.

ANDERLECHT ARREST

At the press conference Friday, the prosecutor's spokesman said Abrini had been arrested in Anderlecht, a gritty mixed district.

Two other people were picked up with him but no details were given of them as police operations in the area wound down just before midnight.

Local television stations showed footage of what was said to be Abrini's arrest, with a man pinned down on the sidewalk by several armed plain-clothed police who bundled the suspect into an unmarked car.

Abrini, a Belgian of Moroccan origin and the last known Paris suspect still at large, was seen at a petrol station north of Paris two days before the attacks with Salah Abdeslam who is now awaiting extradition to France.

The prosecutor's spokesman named two other suspects arrested Friday as Osama K., who went by the alias of Naim Al Ahmed, and Herve B.M.