The Brussels metro station hit by a suicide attack last month that killed 16 people reopened on Monday amid tight security, with a memorial board for passengers to write messages for the victims.

Bomber Khalid El-Bakraoui blew himself up at Maalbeek metro station near the EU headquarters at at 0711 GMT on March 22, an hour after two other Islamic State suicide attackers targeted Brussels airport.

Belgian lawmakers vowed Friday to probe how Belgium failed to thwart the Brussels bombings months after attacks in Paris, as they visited the targeted metro station before it reopens next week.

The parliament's commission of inquiry visited the two scenes of last month's attacks -- Maalbeek station and Brussels Airport -- as part of a mission to shed light by year-end on the attacks in both capitals that were allegedly carried out by the same Islamic State cell.

Belgium said Tuesday that more "terrorist fighters" want to return to Europe from Syria to carry out further attacks, a month after suicide bombings in Brussels killed 32 people.

"There is a lot of intelligence, for example signs that foreign terrorist fighters, combatants in Syria, want to return not just to Belgium, but to Europe to carry out an attack," Paul Van Tigchelt, the head of the government crisis center, told RTBF television.

A Belgium appeals court on Thursday sentenced top jihadist recruiter Khalid Zerkani to 15 years in prison after convicting him of enlisting dozens of people, including key suspects in the Brussels and Paris attacks.

Zerkani is "the biggest recruiter of jihadists Belgium has ever known," Federal Prosecutor Bernard Michel said during a court hearing in February.

A Belgian court on Thursday ordered top Brussels and Paris attacks suspect Mohamed Abrini and six others to be held behind bars for another month.

Abrini, 31, has confessed to being "the man in the hat" caught on video with suicide bombers at Brussels airport on March 22.

Brothers Khalid and Ibrahim El Bakraoui, the suicide bombers who hit Brussels last month, obtained the weapons and explosives for those attacks and for November's carnage in Paris, the Islamic State (IS) group said Wednesday.

The English-language edition of the jihadist group's magazine Dabiq says of Khalid El Bakraoui: "All preparations for the raids in Paris and Brussels started with him and his older brother Ibrahim.

Paris attacks suspect Mohamed Abrini was arrested Friday, a police source told AFP after a Belgian television station said he was detained in a Brussels district.

At the same time prosecutors said police made several arrests in connection with the deadly Islamic State attacks on Brussels airport and metro last month.

Belgian prosecutors on Thursday launched a fresh appeal for help to find the suspected surviving attacker in last month's Brussels airport bombings, the so-called "man in the hat," releasing a video of his escape route.

Police have been desperately searching for the man seen on CCTV next to the two suicide bombers who blew themselves up at the airport on March 22 in coordinated attacks that also struck a Brussels metro station. A total of 32 people died.

The March 22 Islamic State attacks in Brussels represented a security "failure", Belgian Prime Minister Charles Michel admitted Wednesday, but he rejected the notion his country was a "failed state".

Belgian authorities have faced strong criticism at home and abroad for not doing more to prevent the carnage, as links emerged between the Brussels attackers and the jihadists behind the Paris terror assaults in November.

Brussels Airport reopened Sunday with three "symbolic" flights and strict additional checks for passengers, marking a new high-security era for air travel in Belgium after attacks by Islamic State suicide bombers.

The key travel hub has been closed since two men blew themselves up in the departure hall on March 22 in coordinated blasts that also struck a metro station in the Belgian capital, killing a total of 32 people.