The supporters were suspected of planning an unauthorised weekend protest march against an anti-sectarianism law.

A total of 13 people were arrested for alleged public order offences, near Glasgow Cross, as they made their way to a match in Glasgow's Parkhead on Saturday.

MSPs, QCs and independent legal advisers have joined football fans in accusing the police of "harassment, victimisation and disproportionate actions", Labour MSP Michael McMahon told Holyrood.

Mr McMahon said he has already met with the Chief Superintendent in Glasgow to discuss the issues raised on Saturday.

He was joined by Labour MSP Hugh Henry in calling for an independent inquiry to ensure that the Offensive Behaviour at Football Act is not being used to "harass football fans".

Justice Secretary Kenny MacAskill said police may provide "a more accurate picture" of Saturday's events – said to involve members of the Green Brigade – supported by CCTV evidence when it is made public.

He said the Act has an 84% success rate in secur- ing convictions and that he is delighted that action is being taken against Rangers fans recorded singing allegedly sectarian songs at a recent match against Berwick Rangers.

No charges emanating from Saturday relate to the Offensive Behaviour at Football Act.

Mr MacAskill said of Saturday's incident: "Full video footage of the event cannot be released at the moment due to its role in criminal proceedings."

Meanwhile, SNP MSP John Mason, whose constituency includes Celtic Park, has called for tough- er policing around football stadiums to address public drinking and urination.