Two brothers from Kosovo have been arrested by German police on suspicion of plotting to attack the country's largest shopping mall in Oberhausen, near the Dutch border.
The men, aged 28 and 31, were arrested in Duisburg with Germany on high alert following Monday's attack on the Christmas market in Berlin that killed 12 and injured 49.
Friday morning (23 December, around 00:45 hours) special units in Duisburg took two suspicious men into custody," Essen police said in a statement,
"The 28-year old and 31-year-old brothers born in Kosovo are suspected of having prepared a possible attack on the CentrO in Oberhausen," Essen police said.
Investigators were trying to establish what stage of preparation the plot was at and whether others were involved, police in the nearby city of Essen said in a statement.
Tipped off by the intelligence services, police were sent to the shopping mall and a nearby Christmas market late Thursday, they said.
The mall that was targeted, CentrO, is one of the largest in Germany with around 250 shops that are usually packed in the run-up to Christmas.
It is located in an old steelworks in Oberhausen in the former industrial heartland of the Ruhr valley.
Police are still hunting for the perpetrator of Monday's attack on one of Berlin's most popular Christmas markets, believed to be 24-year-old Tunisian Anis Amri.
Isil has claimed responsibility for the assault - their deadliest yet carried out on German soil.