The match takes place at Hampden on Saturday

The Strathclyde force said it was taking the threat of trouble "extremely seriously".

Extra officers are being drafted in and security is being stepped up at ports, airports and train stations ahead of the vital match.

The major police operation will also involve German officers, who are travelling to Glasgow to identify troublemakers.

Police have received intelligence reports suggesting that known hooligans will gather in Glasgow from across Scotland and elsewhere in the UK.

"Officers from Strathclyde have also received information from their German counterparts, warning that rival troublemakers are planning to travel to Scotland," said a police spokeswoman.

Potential trouble

"Strathclyde Police is mounting a massive offensive to counter the threat of hooliganism."

A dedicated intelligence operation has been set up to deal with potential trouble on Saturday.

Chief Superintendent John Malcolm, who will be in command on the day of the match, said the force had been working closely with several Scottish forces, the National Criminal Intelligence Service and German police.

We know who these troublemakers are and I can only stress that if they do come to Glasgow, police will be watching their every move Chief Superintendent John Malcolm

"A number of officers from Germany will be coming over to Glasgow for the match and they will be alerting us to potential troublemakers," he said.

"We are taking this threat extremely seriously, and anyone caught causing trouble will be dealt with severely."

He said genuine Scottish fans had an excellent reputation and were known across the world for their good behaviour.

"This small minority of people intent on causing disruption are not real fans," said Chief Superintendent Malcolm.

"They have complete disregard for the thousands of supporters who want to enjoy the game and cheer on their team.