The militant cell behind bombings in Brussels had intended to launch a fresh strike in France again after carrying out the Paris attacks in November, but was forced to attack in the Belgian capital instead after being “surprised” by a quick-moving investigation, Belgian prosecutors said on Sunday.

“Numerous elements in the investigation have shown that the terrorist group initially had the intention to strike in France again,” Belgium’s federal prosecutor said in a statement.

“Surprised by the speed of the progress in the ongoing investigation, they urgently took the decision to strike in Brussels.”

Investigations into the cell, which was directly involved in the November Paris attacks that left 130 people dead, showed that they had initially planned to stage a second deadly strike in France. It also showed that many of the perpetrators lived in Belgium, including surviving suspects who managed to evade police for more than four months.

Prime suspect Salah Abdeslam was arrested on March 18 in the Belgian capital. Four days later, suicide bombers killed 32 people in Brussels airport and a rush-hour metro train.

Belgian intelligence and security forces had been criticized abroad for not doing more to dismantle the militant cell, because of its links to the Paris attacks.

As of Friday, all publicly identified suspects were either in detention or dead, but Belgium remains on its second highest threat level, and Prime Minister Charles Michel said his government would remain alert.

His comments were echoed by French Prime Minister Manuel Valls, who said France would not be lowering its guard.
Valls said the information that another attack against France was in the works was evidence of the elevated threat to the country.

“It’s extra proof of the very high threats to the whole of Europe and to France in particular,” he said during a press conference in the Algerian capital.
“We will not let our guard down.”

Abdeslam, born and raised in Belgium to Moroccan-born parents, told a magistrate he had planned to blow himself up at a sports stadium in Paris in November, but backed out at the last minute. His brother Brahim blew himself up at a Paris cafe.

Another man linked to the Paris attacks, Mohamed Abrini, was arrested in Brussels on Friday and admitted to being the “man in the hat” captured on video walking into Brussels airport alongside two suicide bombers.

Prosecutors said Abrini , 31, had been charged with “terrorist murders” over the Belgian bloodshed.

“He is charged with participation in the activities of a terrorist group, terrorist murders and attempts to commit terrorist murders.”

“The investigating judge specialized in terrorism cases has put Abrini in detention in connection with the investigation into the Brussels and Zaventem [airport] attacks,” a statement said.

Another main suspect who was seen alongside the suicide bomber in the Brussels metro, identified by prosecutors as Osama K, was also arrested on Friday in the Belgian capital.

Osama K, 28, widely named by media as Swedish national Osama Krayem, was filmed buying the bags used to carry the Brussels bombs.