Berlin attack suspect Anis Amri
Berlin truck attack suspect Anis Amri is seen in these handout pictures acquired from the website of the German Bundeskriminalamt (BKA) Federal Crime Office, Dec. 21, 2016. REUTERS/BKA/Handout via Reuters

A Europe-wide manhunt has been launched for Anis Amri, a Tunisian man suspected of Monday’s truck attack in Berlin that killed 12 people, according to reports Thursday. German officials have issued a wanted notice for the 24-year-old and offered a reward of up to 100,000 euros ($104,000) for information leading to his arrest.

According to German media reports, investigators searched several locations overnight, including a refugee home in Emmerich on the Dutch border. Amri is reported to have entered Germany through Freiburg, a city in the country’s southwest, in July 2015 and was suspected of having ties with the Islamic State group, also known as ISIS. German authorities classified him as a “potential threat” earlier this year, according to German news outlet Spiegel Online.

Officials in Germany have warned that Amri could be “violent and armed.” His brother, Abdelkader Amri, told the Associated Press that the suspect is likely to have been radicalized in a prison in Italy, where he traveled during the Arab Spring uprisings.

Abdelkader also urged his brother to surrender. "I ask him to turn himself in to the police. If it is proved that he is involved, we dissociate ourselves from it," Abdelkader reportedly said.

After the manhunt was issued, police in Denmark searched a Sweden-bound ferry in the port of Grenaa following tip-offs that a person resembling Amri was on the vessel. However, police said they did not find anything.

Monday’s attack, in which about 48 people were injured, was claimed by ISIS. The militant group issued a statement on the ISIS-affiliated Amaq news agency calling the attacker a “soldier of the Islamic State.”

According to a European arrest warrant, Amri was born in the Tunisian town of Ghaza and had half a dozen names — most of them variants of his real name. He also had Egyptian and Lebanese citizenship, the warrant stated.