The suspect is believed to be a refugee from Syria. Police said the man had given his age as 27 and had been living in Germany since 2015.

Security authorities suspect that the as-yet-unnamed suspect acted on behalf of the so-called "Islamic State" (IS) extremist militia.

He was detained in an apartment in the Schoeneberg district and an investigation has begun. Interior Minister Thomas de Maiziere said that German security services have been observing the man for a while before the Wednesday night arrest.

Police referred journalists to Germany's federal prosecutors for further information. Federal prosecutors, who handle most terrorism-related cases, did not name the man but said he is suspected of belonging to the IS group.

Berlin police tweeted approximately 40 minutes after the arrest: "Our state police forces #LKA have just arrested a man suspected of being a member of a foreign terrorist organization."

According to the newspaper "Berliner Zeitung," the Syrian was arrested at about 9 p.m. local time (UTC 20.00). His apartment was also searched, police said.

Authorities have until the end of Thursday to bring him before a judge for a decision on whether they can continue holding him.

In October, authorities detained a man in connection to a Syrian refugee suspected of planning a bombing attack in Germany after police discovered "several hundred grams" of explosive materials at the suspect's residence. The man took his own life in a Leipzig jail.

jbh/kl (Reuters, dpa, AP)