Authorities across Europe are hunting a Tunisian man suspected of killing 12 people in the Berlin Christmas market truck attack, as reports claimed his fingerprints have been found inside the vehicle used.

German authorities have issued a wanted notice for Anis Amri, and offered a reward of up to 100,000 euro (£84,000) for information leading to the 24-year-old's arrest. They warned that Amri could be "violent and armed".

The Sueddeutsche Zeitung newspaper and broadcasters NDR and WDR reported that Amri's fingerprints were found on the driver's door of the Polish-registered truck which caused the mayhem on Monday night.

The daily Berliner Zeitung reported that his fingerprints had been found on the truck's steering wheel.

Meanwhile, one of Amri's brothers in Tunisia has urged him to hand himself in to authorities

Abdelkader Amri said: "I ask him to turn himself in to the police. If it is proved that he is involved, we dissociate ourselves from it."

He said Amri may have been radicalised in prison in Italy, where he went after leaving Tunisia in the wake of the 2011 Arab Spring uprisings.

Several locations across Germany were searched overnight, including a house in the Dortmund and a refugee home in Emmerich on the Dutch border, German media reported.

The manhunt also prompted police in Denmark to search a Sweden-bound ferry in the port of Grenaa after receiving tips that someone resembling Amri had been spotted, but police said they found nothing indicating his presence.

Nearly three days after the deadly attack that left another 48 people injured, the market in the centre of the German capital has reopened, with concrete blocks in place at the roadside to provide extra security.

Organisers at the market decided to ditch party music and bright lighting, and Berliners and visitors have laid candles and flowers at the site in tribute to the dead.

An Israeli woman, Dalia Elyakim, and 31-year-old Italian woman Fabrizia Di Lorenzo of Italy have been identified as two of the 12 people killed in the attack. Ms Di Lorenzo had lived and worked in Berlin for several years.

German officials had deemed Amri, who arrived in the country last year, a potential threat long before the attack - and even kept him under covert surveillance for six months this year, before halting the operation.

They had been trying to deport him after his asylum application was rejected in July but were unable to do so because he lacked valid identity papers, and Tunisia initially denied that he was a citizen.

A document belonging to Amri, who according to authorities has used at least six different names and three different nationalities, was found in the cab of the truck used in the attack.

Family members of Amri, speaking from his hometown of Oueslatia in central Tunisia, were shaken to learn that he was a suspect.

Amri left Tunisia years ago for Europe, but had been in regular contact with his brothers via Facebook and phones.