BERLIN (REUTERS) - Police are investigating a group of football fans in eastern Germany who celebrated their club's victory by marching through town in Ku Klux Klan-style hoods.

After FC Energie Cottbus won promotion to the third-tier of the German league on Sunday, a group of fans, their faces covered with hoods resembling those worn by the US white supremacist group, marched holding a red banner with "The rise of the evil ones", written in gothic script.

The football club called the fans' behaviour "inhumane, repugnant and in no way tolerable," and said they faced a life-long ban from its games if identified.

"We are deeply saddened by the fact that a few people, through their actions, spoiled the joy of victory and damaged the image of tens of thousands of Energie fans and the club," it said in a statement.

The use of extreme-right symbols has particular sensitivity in the city of 100,000 near the Polish border where tensions between far-right supporters and refugees escalated earlier this year after Syrian teenagers were detained over two knife attacks.