Tunisian security forces have arrested the nephew of the Berlin market attacker Anis Amri and two other suspects, officials say.
The Tunisian interior ministry said the three, aged between 18 and 27, were members of a “terrorist cell”, and that they were detained overnight.
Tunisian-born Anis Amri was identified as the attacker who drove the lorry that smashed into a crowded Christmas market in central Berlin on Monday December 19.
Monday’s lorry attack on the market left 12 people dead and 49 injured.
Amri, 24, was shot dead by police in the early hours of Friday after opening fire on police officers during a routine police check in the Milan suburb of Sesto San Giovanni, after a three-day Europe-wide manhunt.
So-called Islamic State (IS) said one of its “soldiers” carried out the attack on Breitscheidplatz Christmas market, without offering evidence.
On Friday, IS released a video showing Amri pledging allegiance to its leader Abu-Bakr al-Baghdadi.
The interior ministry statement said Amri’s nephew – the son of his sister – had confessed that he had communicated with his uncle via the encrypted chat application Telegram to evade security surveillance.
It said the three-member cell had been active in the towns of Fouchana, outside Tunis, and Oueslatia near Amri’s hometown of Kairouan, about 150km (95 miles) south of the capital.
The statement added that Amri had sent money to his nephew to travel to Germany and join a jihadist group, and encouraged him to pledge allegiance to the so-called Islamic State (IS) group.
Meanwhile, intelligence services in Spain are investigating a possible internet communication between Amri and a Spanish resident on 19 December, Interior Minister Juan Ignacio Zoido told radio station COPE.