Two men have been arrested in Germany on suspicion of planning an attack on a shopping centre in Oberhausen near the Dutch border, police say.
The brothers, aged 31 and 28 and born in Kosovo, were detained early on Friday in Duisburg.
Germany is on high alert after Monday’s attack in Berlin, which left 12 dead.
A Europe-wide manhunt continues for Anis Amri, the Tunisian man suspected of driving a lorry into the Breitscheidplatz Christmas market.
Police said the Oberhausen attack had been intended to target the Centro shopping centre.
Officers dressed in civilian clothing had been sent to patrol the centre and a nearby Christmas market after a tip from intelligence services, police said in a statement.
There is no indication so far that Friday’s arrests are linked to the Berlin attack.
German officials have confirmed Anis Amri’s fingerprints were found inside the truck that was used to kill 12 people and wound 49 others in Berlin on Monday evening.
His family in Tunisia have urged him to give himself up to police.
Breitscheidplatz market in Berlin reopened on Thursday, with dimmed lights and no music.
Candles and flowers have been laid for the victims, who include at least six Germans, an Israeli tourist, an Italian woman and the truck’s Polish driver. Police have installed concrete barriers to prevent a repeat attack.
“If my brother is listening to me, I want to tell him to surrender, even for our family. We will be relieved,” Abdelkader Amri said
“I am sure that my brother is innocent. I know why he left home: he left for economic reasons to work, to help the family, he didn’t go for
Both Abdelkader, and another brother, Walid, admitted that Anis had got into trouble in Europe and came out of a three-and-a-half year jail term in Italy with “ he explained.
The German federal prosecutor’s office said Amri’s fingerprints had been found in a number of places around the lorry’s cab. “At this point in the investigation, we assume Anis Amri drove the truck,” said Frauke Koehler.
She also confirmed police raids had been carried out “in various locations” in Berlin and in North Rhine-Westphalia state where the suspect “was living and staying for some time”.
Chancellor Angela Merkel earlier said she was hopeful for a “quick arrest”, and added she was “very proud of how calmly most people” in Germany had reacted to the attack.
Amri was named as a suspect on Wednesday after his identification papers were found in the truck.
A Europe-wide arrest warrant has been issued amid warnings he may be armed and dangerous. The German authorities have offered a reward of up to €100,000 (£84,000; $104,000) for information leading to his arrest.
There is growing criticism of Germany’s security services as details emerge about Amri and his alleged links to Islamist extremists, The 24-year-old, who arrived in Germany in 2015, had been under surveillance by the German authorities this year on suspicion of planning a robbery to pay for automatic weapons for use in an attack.
But the surveillance was reportedly called off after it turned up nothing more than drug-dealing in a Berlin park and a bar brawl.