BERLIN — A German special police unit has detained a Syrian asylum-seeker who they said they suspected of plotting a terrorist attack during the opening of the national soccer league season, German officials said Tuesday.

Germany has been on edge after four attacks in a span of six days last month, including two linked to the Islamic State.

Officers from the special unit arrested the 24-year-old suspect on Friday in the city of Mutterstadt, in the western state of Rhineland-Palatinate, after the authorities in Duisburg received a tip about a possible attack, the Interior Ministry in neighboring North Rhine-Westphalia said. The suspect has been questioned and will remain in detention pending the outcome of the investigation, the ministry said.

Michael Maurer, a spokesman for the Interior Ministry in the state of Rhineland-Palatinate, said there had been indications that the suspect was plotting an attack directed at the opening of Germany’s top soccer league, the Bundesliga, later this month.