Tunisian authorities say they have arrested the nephew of the slain Berlin truck attack suspect, Anis Amri, and two others suspected of belonging to the same extremist network.
The three suspects, aged between 18 and 27, were members of a "terrorist cell...connected to the terrorist Anis Amri who carried out the terrorist attack in Berlin,” Tunisia's Interior Ministry said in a statement on December 24.
The ministry said that Amri, a Tunisian national, had sent his 18-year-old nephew Fedi money to join him in Europe and encouraged him to pledge allegiance to the Islamic State (IS) extremist group.
The Tunisian Interior Ministry said that the "terrorist cell" was "active" between Fouchana, south of Tunis, and Oueslatia, the hometown of Amri's family in central Tunisia.
Amri, 24, is suspected of having driven a truck into a Berlin Christmas market late on December 19, killing 12 people and injuring dozens. Police say his fingerprints and wallet were found in the truck.
An IS-affiliated news agency said on December 20 that IS inspired the attack and called the assailant "a soldier of the Islamic State."
Amri was shot dead after pulling out a pistol and firing at two Italian police officers who had stopped him for a routine identity check near Milan's Sesto San Giovanni railway station on December 23.
Shortly after Amri’s death was confirmed, IS released a video in which he is shown pledging allegiance to the militant group’s chief Abu Bakr al-Baghdadi.
Meanwhile in Spain, police say they are investigating whether Amri was in contact with another possible extremist in Spain.
Spanish police are looking into a tip passed on by German authorities that Amri had developed a contact in Spain, Interior Minister Juan Ignacio Zoido said on December 24.
"We are studying all possible connections [between Amri] and our country, above all with one specific person," the minister told Spanish radio station Cope.
In Germany, a spokesman for the Berlin police said on December 24 that there would be an increased presence of uniformed and plainclothes officers on the streets of the capital over the Christmas holidays.