Berlin attack: 'Four arrested' after Christmas market killings

Police storm house in Dortmund as hunt continues for suspect Anis Amri

Police officers guard the Christmas Market in Stuttgart (AP)

Four people have reportedly been arrested in Germany as a Europe-wide search continues for the suspected Berlin attacker.

Armed police stormed a house in Dortmund early on Thursday morning, detaining four people inside, Bild reported. The newspaper published photos of officers at the scene and taking a suspect covered in a towel into custody.

They were believed to have links to Anis Amri, a 24-year-old Tunisian man being hunted across Europe following the massacre at a Christmas market in Berlin.

A spokesperson for Germany's Federal Public Prosecutor, which is leading the terror investigation, said the report was "totally false".

But officials at North Rhine-Westphalia police did not deny the operation took place and The Independent understands more details may be released later.

Amri has been linked to an Islamist network in the region and is thought to have followed a Dortmund-based extremist called Boban S, who was arrested earlier this year for supporting Isis.

Residents living near Boban S' former home told Ruhr Nachrichten they recognised Amri, last seeing him around 10 months ago.

The suspect has also been linked to a hate preacher in Hildesheim known as Abu Walaa, who was detained last month as part of a group radicalising Isis militants and sending them to Syria.

Migrant accommodation where Amri formerly lived in Emmerich has also been searched by police, who did not give details of the operation.

The Tunisian suspect had his asylum claim denied by Germany but could not be deported because the necessary paperwork proving his nationality was missing.

As well as using at least six aliases, Amri used fake identity documents and claimed to be Egpytian or Lebanese at various points as he travelled around Germany after arriving in July 2015.

He was the subject of a previous investigation over a possible terror plot and was put under surveillance in March, but the operation was ended in September because of a lack of evidence.

Prosecutors are offering a €100,000 (£85,000) reward for information leading to Amri's arrest, warning people not to approach the “violent and armed” suspect.

There were fears the attacker could pose a further danger to Germany after killing 12 people and injuring around 50 more on Monday.

The hijacked lorry’s driver was found shot dead inside but the gun used has not been found.