Belgian prosecutors said Thursday they were looking for further suspects in an emerging probe into terrorist activity and feared a possible fresh attack in Belgium.

“We are still looking for several terrorism suspects,” Eric van der Sypt, the spokesman for the federal prosecutors’ office, said.

“We fear they may feel cornered. We therefore fear there could be the same reaction as on March 22 (2016),” he told VTM television.

Van der Sypt was referring to suicide bomb attacks in Brussels on March 2016 which killed 32 people as police closed in on an ISIS cell linked to the November 2015 Paris killings.

One of the Brussels bombers was later found to have left a will on a laptop computer in which he said the gang felt increasingly cornered and desperate.

Separately, RTL news network cited Van der Sypt as saying: “One can never know how these people might react.”

The authorities however had no “new element” suggesting that an attack was imminent, he added.

On Wednesday, police charged two brothers of a convicted militant with belonging to a “terrorist group” they suspected of planning an attack after finding a large stash of weapons including Kalashnikov rifles in raids overnight.

The pair, named as Akim and Khalid Saouti, were among four people detained in the Brussels district of Anderlecht, two of whom were later released.

In the same operation, which was conducted in cooperation with French police, a fifth person was detained across the border in the northern French city of Lille.

A source with knowledge of the French operation said this man, who fled the house but was detained in an adjacent street, was suspected of planning a “violent attack.”

Another source close to the Brussels probe said the two men in custody were brothers of Said Saouti, a member of the Kamikaze Bikers club who was jailed for six years in 2016 for recruiting people to terrorist organizations and supporting ISIS on social media. 

The Belgian federal prosecutor’s office said police found automatic rifles, handguns, ammunition and bulletproof vests as well as police and security guards’ uniforms and “four detonators” in a lock-up garage in Anderlecht. 

Authorities were drawn to the Saouti brothers on suspicion that they had been radicalized and were planning an attack, according to reports.

A spokesman for prosecutors had said earlier that the raids were “directly linked” to members of the Kamikaze Riders, not to the investigation into the Paris and Brussels attacks.

Several members of the Kamikaze Riders, formed in 2003 and known for testing the patience of the police, were suspected of links to foiled attacks in Brussels in late 2015.

In October 2016 two members of the gang, including Said Saouti, were convicted of belonging to a terrorist group.

They were originally suspected of plotting an attack similar to the November 2015 carnage in Paris that left 130 people dead. 

Four months later, the jihadists also struck in Brussels, hitting the airport and the metro, killing 32 people and leaving hundreds injured.