German police have arrested a 24-year-old Syrian refugee after receiving a tip-off that he was planning a possible Islamist-motivated attack, state officials in North-Rhine Westphalia said on Tuesday.
Germany, Europe's economic powerhouse and the destination for more than 1.3mn migrants in the past year, is on high alert after two attacks claimed by Islamic State that left several injured and the two attackers dead.
The Syrian man, who was arrested in the neighbouring state of Rhineland-Palatinate on Friday, remains in police custody, the North-Rhine Westphalia interior ministry said in a statement.
"Investigations conducted thus far have found no evidence of a concrete threat," it said.
Earlier, Germany's Bild newspaper said the authorities had arrested what it called "a suspected high-ranking Islamic State militant" in the town of Mutterstadt.
But a spokesman for the North-Rhine Westphalia interior ministry later told Reuters that "the man arrested was not a high-ranking member" of IS.
German public broadcaster SWR said he was born in Damascus and arrived in Germany as a refugee in early 2016. It said the state prosecutors office in Duisburg had been observing him as part of an investigation.
Both SWR and Bild said that authorities were investigating a possible attack at the start of the season of Germany's top soccer league, the Bundesliga, on August 26.
"There are indications that something was being planned for the start of the Bundesliga season," an interior ministry official from Rhineland-Palatinate in Mainz was quoted saying.
Bild said in its online edition that the man had been arrested during a police stop. It said the authorities had received a tip-off about the man from a prison in North Rhine-Westphalia.