BERLIN • German police have detained a teenage asylum seeker suspected of planning a suicide attack in Berlin, a spokesman for the interior ministry of the neighbouring state of Brandenburg said.

The 17-year-old suspect, who is believed to be Syrian, although his nationality has not been confirmed by the police, was arrested yesterday in the Uckermark region in Brandenburg, north-east of Berlin.

Special forces arrested the teenager after police received a tip-off, Brandenburg police said in a tweet made in German, the BBC reported. The suspect had sent a farewell message to his family and said he was joining the "jihad", the police added.

The teen told his family he planned to carry out a suicide attack, said Brandenburg Interior Minister Karl-Heinz Schroter, whose office had said the suspect was Syrian.

Police, however, said neither the suspect's nationality nor his "concrete attack plans" could be confirmed yet as investigations continued, according to Reuters.

The teenager, who came to Germany in 2015, had been living in a home for unaccompanied underage refugees in Uckermark since last year. He had never been brought to the attention of the police, the BBC reported.

Memories are still fresh in Germany of the Berlin Christmas market attack in December last year, when 12 people were killed by a failed asylum seeker who had pledged allegiance to the Islamic State in Iraq and Syria (ISIS).

Last Wednesday, police arrested four suspected terrorists in raids in Berlin as the German capital geared up for a long weekend of mass gatherings, capped by a joint appearance by Chancellor Angela Merkel and former United States President Barack Obama.

German media N-TV, citing intelligence service, said ISIS has placed Germany as Europe's top target.

The number of extremists in Germany has grown to 10,000 from around 8,650 last year, Xinhua reported.