It has been five years since Islamist bombers slaughtered 32 people in the Belgian capital Brussels, in an attack then prime minister Charles Michel says changed the country forever.

In an AFP interview, Michel -- now the president of the European Council and host of EU summits in the city -- said he was still marked by the events of March 22, a "terrible shock" that had a lasting impact.

"The country is not the same after those attacks. A threat that until then we'd thought of as theoretical is now very real," said Michel, a liberal leader who was Belgium's prime minister between 2014 and 2019.

"I am still marked by the moment I received the information. When the minister of the interior called to inform me, within minutes of the attack in Zaventem, I left directly for Brussels, heading for the crisis centre," he said.

The first double suicide bombing targeted travellers at Brussels airport in Zaventem, just outside the city, but an attacker would also hit the heart of the capital, close to Michel's office and the headquarters of the EU institutions.

"As we were driving back to the city, near the Metro, we drove over broken glass and I learned that there had been an explosion there too," Michel said.

"You really get the feeling that other attacks will follow (...) in a coordinated, synchronised action. In the following days we were living in a state of siege, security had become an obsession," he said.

Michel approved the extension of police custody periods and authorised night raids by officers investigating terrorist cases.

He also reinforced the presence of uniformed military in the streets, still an occasional sight protecting transport hubs, public buildings and synagogues today.

The troops had been deployed the year previously, after the dismantling of a jihadist cell, and Belgium was on guard after attacks in November 2015 on Paris that left 130 dead and were linked to a cell based in Brussels.

Charles Michel, who was Belgium's prime minister, recalls the 'terrible shock' of the bomb attacks in Brussels five years ago. Michel, in the centre, is pictured heading to a makeshift memorial the day of the events
Charles Michel, who was Belgium's prime minister, recalls the 'terrible shock' of the bomb attacks in Brussels five years ago. Michel, in the centre, is pictured heading to a makeshift memorial the day of the events AFP / KENZO TRIBOUILLARD

One of the three suicide bombers of 22 March had been arrested in Turkey and then deported in the summer of 2015, but he slipped under the radar of the intelligence services on his return to Belgium via the Netherlands.

This caused a heated political row two days after the attacks.

The Belgian authorities had been "informed that this individual was a foreign terrorist fighter", according to Turkish President Recep Tayyip Erdogan.

In Brussels, interior minister Jan Jambon and justice minister Koen Geens offered their resignation, but Michel refused to let them go.

"Officers do not abandon ship in a storm, there was no personal fault on the part of either of them," he told AFP, just ahead of the anniversary.

"It would have been irresponsible to add to a political crisis to a time of maximum security pressure. Belgium had not experienced such acts of violence since World War II."

Prior to the jihadist attacks, modern Belgium's most notorious incidents of violence were a spate of bombings by a leftist faction in that left two dead, and the unsolved murders by the "Mad Killers of Brabant".

This series of shootings, robberies and apparently senseless attacks left 28 dead and the nation shaken, but remain a mystery to this day, despite theories that they were carried out by far-right extremists with ties to intelligence or security forces.

Neither campaign matched the scale of the bombings unleashed by militants linked to the Islamic State Group. In addition to the 32 dead, another 340 were hurt, many of them grievously in crowds in the airport and metro station.

Immediately after the November 13, 2015 attacks in Paris, the French investigation revealed that some of the attackers came from Brussels.

The Brussels district of Molenbeek, with a large Muslim population of mainly North African descent, became notorious around the world as a supposed haven for jihadists.

The US news outlet Politico dubbed Belgium a "failed state", a term that spread and threatened to catch on but, looking back now, Michel thinks perceptions have changed, despite the country's reputation for political chaos.

"In the international imagination, there was still the fresh memory of the 541 days it took my predecessor to form a government," he admitted, but in the wake of Brussels' own attacks and security crackdown he received calls of support from London and Washington.