An Iraqi national tipped off German police about a possible terrorist attack eight days before intelligence from the United States and France led authorities to evacuate two Munich train stations on New Year's Eve, Bavarian media reported Sunday.

On December 23, an Iraqi man went to a police station in the southern state of Baden-Wuerttemberg and claimed his brother, who lives in Iraq, knew the terrorists that were planning to carry out the attack, Suedwestrundfunk and Bayerischer Rundfunk radio stations reported.

State police subsequently interviewed the man's brother, who claimed the attacks would be carried out around January 6 - the feast of the Epiphany, a Christian holiday observed in Bavaria - on Munich's train network.

He gave the names of seven terrorists who he said were already in Munich at that time.

State police and Germany's foreign intelligence agency BND failed to locate the individuals named by the Iraqi man, and two raids on Munich apartments on December 30 did not yield results, the report said.

On New Year's Eve, German authorities received a "very concrete tip" of an imminent attack from intelligence sources in the US and France, causing them to evacuate Munich's central and Pasing train stations.

No arrests have been made since and it remains unclear whether the people whose names were given to the authorities are even in the country.

During the night of Saturday to Sunday, Bavarian police temporarily evacuated 13 people from residential buildings surrounding Pasing station after a sniffer dog detected explosives in a payphone inside the station.

The threat was investigated and found to have been a false alarm.

Germany's intelligence service estimates that around 1,100 potentially violent pro-Daesh suspects are currently living in the country, 430 of whom have already committed serious crimes.