Fears of Fresh European Terror After Paris Attacker's Arrest in Brussels

Following Abdeslam's arrest in Brussels on Friday, security authorities have remained cautious, with Belgium maintaining its level-three alert, while French officials have reinforced checks on the border with Belgium amid fears of reprisal attacks from terrorists operating in Europe.

"We fear that Abdeslam's arrest activates other terrorists cells," Belgian interior minister Jan Jambon told Bel RTL radio.

"The network remains active in Europe," he said, noting that the investigation had uncovered more people involved in the terror operation than previously thought.

Security and law enforcement officials suggested the terror suspect may have been planning an attack in Brussels prior to his arrest, with heavy weapons and ammunition found during an earlier raid in an apartment in the Brussels district of Forest, where traces of Abdeslam's DNA was later found.

"When you have weapons and terrorists at the same place, that means an attack was being prepared," Jambon said.

Fears of More Attacks

The arrest of Abdeslam appears to have uncovered far more extensive jihadists cells than previously thought, turning the attention once again to homegrown European terrorism, and in particular, hotspots such as Brussels' Molenbeek district, where the suspect had been living prior to the Paris attacks.

Molenbeek, which following the Paris attacks was labeled the 'jihadi capital of Europe', was one of many areas identified as having concerning levels of radicalization and extremism.

The situation in the district was considered so bad that interior minister Jambon declared in November: "We don't have a grip on the situation in Molenbeek," which is home to large immigrant communities and suffers from unemployment levels approximately three times the national average. 

Critics have blamed inaction of behalf of Belgium's law enforcement authorities, along with the social isolation of the country's Muslim community and increased online recruitment from terrorist groups as reasons why Molenbeek has developed into one of the Europe's most radicalized districts.

The concerns, which are also echoed in some suburbs of Paris, have led to fears about the prevalence of terror groups in the heart of the EU, with calls for the bloc's passport-free travel area, known as the Schengen zone, to be suspended to stop the flow of terror cells from operating across national borders.

Others say governments should try to stem the tide of social segregation and isolation of immigrant communities, amid fears the current social climate, along with international terror trends, could result in a generation of increased jihadist activity in Europe.