PARIS — Dozens of terror suspects were arrested in European raids early Friday as authorities cracked down on alleged Islamist extremists in the wake of deadly attacks in Paris and a shootout in Belgium.
Thirteen people were detained across Belgium in what authorities said was an operation to dismantle a terrorist cell that planned to "kill several policemen in the street and police stations," federal magistrate Eric Van der Sypt told reporters on Friday.
Four Kalashnikov assault rifles and explosives were recovered along with police uniforms, communications equipment, false documents and a significant amount of cash, according to officials. Van Der Sypt said the murder plot was "within hours or days" of being launched.
Prosecutors said Thursday that the suspects had been preparing "terrorist attacks on a grand scale." Van Der Sypt said investigations into the Belgian suspects began before the Paris attacks and no link had been found to the Charlie Hebdo attackers.
Van der Sypt added that more suspects could be at large. "I cannot confirm that we arrested everyone in this group," he told reporters.
On Thursday, Belgian police launched raids in the town of Verviers in which two other terror suspects were killed in a firefight. Officials said that operation was part of a crackdown on Islamist extremists returning from Syria.
Twelve people were also detained in the French capital, the spokeswoman for the Paris prosecutor's office told NBC News. She said the suspects were being questioned on whether they provided transport, weapons and logistics to the perpetrators of the three days of bloodshed in the city that left 17 dead.
French authorities have vowed to track down accomplices to Charlie Hebdo gunmen Said and Cherif Kouachi and kosher supermarket hostage-taker Amedy Coulibaly, who were killed by police on Jan. 9. Coulibaly's common-law wife Hayat Boumeddiene is believed to have fled to Syria.
French Interior Minister Bernard Cazeneuve said the raids occurred in several Paris suburbs. They were the result of intelligence gathered by an anti-terror unit set up inside the Interior Ministry on the first day of the attacks, he told a news conference on Friday.
In Berlin, some 250 officers searched 11 properties and arrested two Turkish nationals in overnight raids. They were suspected of supporting and recruiting Syrian fighters and planning attacks in the Middle Eastern country.
The men detained were a 41-year old only identified by officials as Ismet D. and a 43-year-old identified as Emin F. "We believe that the men have been providing logistical and financial support to fighters in Syria," prosecutor's spokesman Martin Steltner told NBC News.
The Berlin raids were the culmination of a months-long investigation into the men, according to a statement by the Berlin Police. As well as allegedly recruiting fighters, the men are accused of providing significant amounts of money and military-grade equipment, such as night-vision devices, to foreign fighters in Syria.
Officials have found no concrete evidence of attacks being planned in Germany, the statement added.
Authorities in Paris said the Berlin raids were not coordinated with those in France.
But Elmar Thevessen, a terrorism expert with NBC News' German partners ZDF, said that a message was clearly being sent to "the Islamist scene that they are under surveillance after the Paris attacks." He added that officials wanted to prevent "copycat attacks and get reassurance that they have not missed any attack plans."
Raffaello Pantucci, director of international security studies at London's Royal United Services Institute (RUSI) think tank, added: “I think the raids that we’ve seen take place in Germany and some other European countries overnight reflect a reality of concern across the continent. I think after the events in Paris, authorities across Europe started to look again at lots of their networks and tried to arrest and pick up people who previously may have been of less concern."
A day earlier, authorities in the northwest German state of Lower Saxony arrested a 26-year-old man suspected of having joined ISIS. He was identified as Ayub B., who is of German and Tunisian citizenship.
Germany's attorney general's office said in a statement that the man was suspected of travelling to Syria in May and returning to Germany in August. "He is suspected of receiving military training there and having helped to recover dead and hurt fighters from the battlefield during a military offensive," the statement added.
Some Jewish schools in Belgium and the Netherlands were closed Friday in the wake of the operation.
NBC News' Jake Cigainero, Charlene Gubash and Michele Neubert, Reuters and The Associated Press contributed to this report. Alexander Smith and Carlo Angerer reported from London.