Police in Belgium made three arrests Saturday in connection with Friday's bloody terror assaults in Paris that killed at least 129 people, officials said.

Belgium Justice Minister Koen Geens told the VRT network that the arrests came after a car with Belgian license plates was seen Friday night close to the Bataclan concert hall, scene of the deadliest assault where at least 89 people were massacred by attackers armed with AK-47s and explosives.

Geens said the car was a rental and the arrests stemmed from police raids conducted in the St. Jans Molenbeek neighborhood in Brussels.

Earlier Saturday, French media reported that a suspicious black car with Belgian places was seen near the Bataclan, Sky News reported.

Late Saturday, the area around the Eiffel Tower was evacuated, the Champ de Marspark underground station was closed and there was heavy police activity for a time around the Pullman Hotel, as French authorities continued to hunt the Islamic militants responsible for Friday's deadly attacks. The scenes were eventually cleared.

Paris prosecutor Francois Molins told a news conference Saturday evening in Paris that the seven gunmen involved in the attacks all wore suicide vests containing the explosive TATP, a chemical used in other major terrorist attacks such as the London bombings of 2005, Molins said, according to the Wall Street Journal. All the attackers either killed themselves by detonating their vests, or were shot by police, Molins said, according to the paper.

“We can say at this stage of the investigation there was probably three coordinated teams of terrorists behind this barbaric act," the prosecutor said, according to Reuters.

The swift arrests in Belgium came as France’s president Francois Hollande vowed to punish ISIS for the attacks and French anti-terror police hunted Saturday for potential accomplices to the attackers.

The terrorists teams carried out their coordinated attacks Friday night at six sites around the capital, authorities said.

Police pursued numerous leads Saturday as they sought to identify the dead terrorists, determine if they were they only ones involved and track down anyone who may have provided assistance.

Two French police officers told the Associated Press Saturday that one of the suicide bombers was identified as a young Frenchman flagged in the past for links with Islamic extremist activity.

The officials said the man was one of the four attackers who blew himself up after a rampage and hostage-taking at the Bataclan. Molin said he had a criminal record with eight arrests.

Earlier Saturday, police officials said they found a Syrian passport on the body of a suicide bomber at another site targeted in the assaults, the Paris soccer stadium where three were killed. The other victims were killed in bursts of gunfire at restaurants in two popular Paris neighborhoods.

Molins said the attacker with the Syrian passport was not known to French intelligence services.

A Greek official said that terrorist crossed into the European Union through the Greek island of Leros in October, a transit point for Syrian refugees fleeing their war-torn country.

A second suspected attacker was likely to also have come through Greece, a Greek official told Reuters.

Citizen Protection Minister Nikos Toskas, in charge of police forces, issued a statement that said,  "On the case of the Syrian passport found at the scene of the terrorist attack, we announce that the passport holder had passed from Leros on Oct. 3 where he was identified based on EU rules.”

"We do not know if the passport was checked by other countries through which the holder likely passed," Toskas added.

The BBC, citing British officials, reported Saturday that the attackers were members of a self-contained cell and had travelled to Syria.

Hollande called the attacks "an act of war" as he promised Saturday to hit back at ISIS, which claimed responsibility.

His comments came after he declared three days of national mourning and he and top aides held an emergency security meeting to plan his government’s response.  

Hollande had previously declared a state of emergency in France, the first such declaration in decades. He also ordered stepped-up scrutiny at the country’s borders. Parisians were told to stay at home Saturday as the Eiffel Tower and other tourist attractions were closed.

The investigation into the attack involves hundreds of counter-terrorism officers and was being led by the Paris prosecutor’s office.

A spokeswoman for the prosecutor Agnes Thibault-Lecuivere said authorities couldn’t rule out the possibility that other militants involved in the attack remained at large.

As part of the investigation, French police were reviewing hours of surveillance video. They also urged any witnesses to come forward.

Those killed at the Bataclan had gone to the venue for a performance by the California rock bank Eagles of Death Metal. Witnesses said the gunmen were wearing black and white kaffiyehs.

Investigators were checking another potential lead from Germany where the governor of Bavaria said Saturday that a 51-year-old man arrested last week near the German-Austrian border with weapons in his car may be linked to the Paris attacks.

A spokesman for Bavarian state police confirmed earlier Saturday that firearms, explosives and hand grenades were found when police stopped a man on Nov. 5. Ludwig Waldinger declined to confirm reports by public broadcaster Bayrischer Rundfunk that the man appeared to be en route to Paris when he was arrested.

Responding to questions about the Paris attacks, Bavarian governor Horst Seehofer said: "In the course of spot checks we had an arrest where there are reasonable grounds to assume that there may be a link to the matter." He didn't elaborate in his comments broadcast by Bayrischer Rundfunk.

Germany's interior minister said French authorities were informed of the arrest at the time, because of the possible link to France. Thomas de Maiziere said the arrested man's navigation device contained an address in Paris, but he urged against making a hasty link to the terror attack.

"There is a connection to France but it's not certain that there is a link to this attack," de Maiziere told reporters in Berlin.

Citing unidentified investigators, Bayrischer Rundfunk reported that documents found during the arrest indicated that the man was from Montenegro and was traveling to Paris. It also reported that the weapons, which it said included an automatic rifle and one kilogram of TNT, were professionally hidden inside the body of the car, a VW Golf.

The Associated Press contributed to this report.