A French prosecutor said on late Saturday that three teams of DAESH attackers carried out the bloody Paris attacks which have so far left 129 people dead and 352 wounded, with 99 remaining in critical condition.
Speaking in a press conference on Saturday evening, Paris Chief Prosecutor Francois Molins told reporters that "We can say at this stage of the investigation there were probably three co-ordinated teams of terrorists behind this barbaric act."
Molins said seven assailants were killed during the attack who were heavily armed and wore suicide wests.
One of the attackers was identified as a 29-year-old French citizen whose remains were found near the Bataclan concert hall in eastern Paris.
The assailant had a criminal record but had never spent time in jail or been involved in a counter-terrorism investigation, according to Molins.
At least one Syrian passport was found at the scene of the attacks, raising suspicion that some of the assailants may have crossed to Europe with refugee groups coming in from Syria.
"A Syrian passport in the name of a person born in Syria in September 1990 was found near a suicide bomber who blew himself up at the Stade de France [stadium]," Molins said.
The Greek Minister for Citizen Protection Nikos Toskas also said, "We confirm that the [Syrian] passport holder came through the Greek island of Leros on October 3 where he was registered under EU rules."
It is not yet known whether the passport belonged to one of the attackers.
French police said an Egyptian passport has also been found in connection with attacks.
Following the bloody attacks, investigations were extended beyond France.
Three people, including a Frenchman, were arrested near the Belgian-French border by Belgian police on Saturday.
Belgian Prime Minister Charles Michel said all the detentions were linked with "suspect vehicles" which were seized during the investigation by Belgian police. He also added that one of the arrested was in Paris at the time of attacks.
Belgian police said one of the "suspect vehicles" was a black SEAT used in two attacks.
Another one was a black Volkswagen Polo that was found at the concert hall where at least 88 hostages were killed by the attackers.
According to the police, the last vehicle was rented by a Frenchman who was living in Belgium before the attacks.
Germany also joined the investigations, searching for the suspects of the attacks.
Last week, a man was arrested with a car which was filled with weapons and explosives and now German police are looking for possible links between the arrest and the attacks.
Following the attacks, French President Francois Hollande said the attacks were "prepared, organised and planned overseas, with help, from inside [France]."
The domestic intelligence and security service of the United States, The Federal Bureau of Investigation (FBI), also plans to send a team to assist the investigations in Paris.