A masked Belgian police officer takes part in police operations in Schaerbeek following Tuesday's bomb attacks in Brussels, Belgium, March 25, 2016. REUTERS/Vincent Kessler

Police arrested six more people linked to Tuesday's terror attacks in Brussels Thursday night in raids around the Belgian capital, prosecutors said.

In a statement late Thursday, prosecutors said the arrests were made during raids in central Brussels, Jette and the Schaerbeek neighborhood, the Associated Press reported. Police said they found a large stash of explosives and other bomb-making material earlier this week in an apartment in Schaerbeek believed used by the suicide bombers.

SWAT teams and armored cars, with helicopter support overhead, began the raids soon after 9 p.m. local time, Belgian state broadcaster RTBF said, citing police sources.

The arrests came two days after suicide bombers hit the Brussels airport and a metro train, killing at least 31 people and wounding some 270 in the worst such attack in Belgian history.

Authorities have not released the names of any of those arrested, the Guardian reported. But police had been searching since Tuesday for a man seen with the two suicide bombers at Zaventem airport, along with others who may be implicated in planning the attacks. It is not known if any of those arrested Thursday are the two men – one from the airport and one from the metro station – who it is thought might have escaped the blasts on Tuesday.

'High-level' arrest

In France, meanwhile, a man suspected of having ties to a militant network planning an attack was arrested Thursday morning, French Interior Minister Bernard Cazeneuve said.

The arrest helped "foil a plot in France that was at an advanced stage," Cazeneuve said Thursday night in a televised address from his ministry, Reuters reported.

"The individual questioned, a French national, is suspected of high-level involvement in this plan. He was part of a terrorist network that planned to strike France," Cazeneuve said.

Following the arrest by the French counterterrorism service, DGSI, the agency carried out a raid on Thursday night at an apartment building in Argenteuil, a suburb in northern Paris, he said.

Cazeneuve said, however, that no link between the Argenteuil arrest and the investigations into Paris and Brussels attacks had been established "at this point," France Info reported.

Resignation offers

Earlier Thursday, Belgium's interior and justice ministers offered to resign over a failure to track an Islamic State group militant expelled by Turkey as a suspected fighter and who blew himself up at the Brussels airport, Reuters reported.

Brahim El Bakraoui was one of three identified suicide bombers who hit the airport and metro train. At least one other man seen with them on airport security cameras is on the run, and a fifth suspected bomber filmed in the metro attack may be dead or alive.

Bakraoui's brother Khalid, 26, killed about 20 people at Maelbeek metro station in the city center. De Morgen newspaper said he had violated the terms of his parole in May by maintaining contacts with past criminal associates, but a Belgian magistrate had released him.

Interior Minister Jan Jambon and Justice Minister Koen Geens tendered their resignations to Prime Minister Charles Michel, who asked them to stay on. "In time of war, you cannot leave the field," said Jambon, a right-wing Flemish nationalist.

Belgian Vice-Prime Minister and Interior Minister Jan Jambon (left) and Belgian Minister of Justice Koen Geens both offered to resign after Tuesday's terror attacks in Brussels. Thierry Charlier/AFP/Getty Images

Turkish President Tayyip Erdogan said Bakraoui, 29, had been expelled in July after being arrested near the Syrian border and two officials said he had been deported a second time. Belgian and Dutch authorities had been notified of Turkish suspicions that he was a foreign fighter trying to reach Syria.

At the time, Belgian authorities replied that Bakraoui, who had skipped parole after serving less than half of a nine-year sentence for armed robbery, was a criminal but not a militant.

"You can ask how it came about that someone was let out so early and that we missed the chance to seize him when he was in Turkey. I understand the questions," Jambon said. "In the circumstances, it was right to take political responsibility and I offered my resignation to the prime minister."

Investigators are convinced the same jihadist network was involved in the November Paris attacks.

Belgian public broadcaster VRT said investigators believed that Paris attacks suspect Salah Abdeslam, arrested last Friday, probably planned a similar shooting and suicide bomb attack in Brussels.

One man was killed in a shootout with police on March 15 that led to the discovery of assault weapons and explosives and the arrest of Abdeslam, 26, and another suspect on March 18.

Belgium lowered its security alert level one notch to three from the highest level, four, but officials did not say what that would mean in terms of security measures that have included a heavy police and military presence in Brussels.

The Islamic State group, also known as ISIS or ISIL, posted a video on social media calling the Brussels blasts a victory and featuring the training of Belgian militants suspected in the Paris attacks.

The lawyer for Abdeslam said the French national wanted to "explain himself" and would no longer resist extradition to France. His lawyer, Sven Mary, said Abdeslam had not been aware of the plan for the Brussels airport and metro attack that was carried out by men who had shared hideouts with him.

Two sources familiar with the matter said the Bakraoui brothers had been on U.S. government counterterrorism watch lists before the attacks. But it was not clear how long they had been known to the authorities.