Anti-terror police have launched an investigation after it emerged that the head of religious events at Glasgow Central Mosque, Sabir Ali, held senior positions in the UK branch of the group Sipah-e-Sahaba (SSP) – an organisation responsible for terrorist atrocities in Pakistan.

In documents uncovered by the BBC, the organisation's own publication suggests that both Ali and Hafiz Abdul Hamid, a leader at Edinburgh's Polwarth Mosque, had connections with SSP after it was banned.

SSP was proscribed by the UK government in 2001 and then by the government of Pakistan in 2002 for violence against the Shi’a community.

Documents show that a memorial to assassinated former SSP leader and co-founder Azam Tariq was held at Glasgow Central Mosque in 2003.

Magazine Khalifat-e-Rashida claims a man named Chaudhry Sabir told those attending that Tariq had “won the hearts of the Muslim world” and that “the enemies of Islam killed him” before he vowed to continue Tariq's mission.

According to the magazine, Azam Tariq had also been hosted by Sabir Ali in Glasgow on a number of occasions in the 1990s.

Chief Superintendent Paul Main said his officers have not yet spoken to Sabir Ali or Hafiz Abdul Hamid but an investigation was launched this morning.

He said: "We will seek to try to verify the claims in the media.

“That investigation will take place at the Scottish Crime Campus in Gartcosh.

“It's hard to say how long that will take but we will make every effort to get to the bottom of this as quickly as possible.”

He added: “There is a range of legislation available. There is an offence under the Terrorism Act about being a member of a proscribed organisation.”

Leaders at Glasgow Central Mosque held a press conference yesterday, along with members of other denominations and faiths.

Sabir Ali was not invited to attend, however he has not yet been suspended from his role as head of religious events at the Mosque.

Glasgow Central Mosque Trustee Mohammed Ashraf said: “Once the results of the investigation are clear we will take appropriate action.”

Lawyer Aameer Anwar, who chaired the press conference, said: “There are no excuses for SSP, from this platform, from out Mosque, from the community. SSP are a Sunni sectarian group of killers who have targeted Shi'as, Christians, Ahmadis and in fact any of us who oppose their twisted version of Islam.

“A very small minority of our community may think it is ok to meddle in the cesspit of violence or extremist politics of Pakistan. They may think if it happened in Pakistan it causes no concern here.

“But we are all united in saying we do not want to import sectarian violence that has caused so much division and bloodshed in Pakistan. Those individuals must realise if they try to import such hatred into our communities we will not stand idly by and watch.”

Chief Superintendent Main said: “Scotland, like many other parts of the world, is not immune from extremism and has suffered violent fatal terror attacks in the past, which have not been inspired by people in Scotland or committed by people resident in Scotland. But that should not make us complacent.

“Communities exist in a global context where extremist views from all over the world are easily shared. Our challenge, all of our challenge, is to work together to prevent radicalisation, extremism and terrorism in all our communities.”

Representatives of the Muslim Council of Scotland, Glasgow Central Mosque, New Mercy Asian Church and the Ahmadiyya Muslim Community Glasgow all condemned extremism.

Imam Habib ur Rehman of Glasgow Central Mosque also spoke about an article in The Herald last week which revealed he praised Islamist assassin Mumtaz Qadri as a “true Muslim” and equated his actions with the French resistance against the Nazis during the Second World War.

He said: “In recent days I’ve experienced feelings of immense sadness and despair. In addition to all the atrocities around the world, I found myself in a situation where some comments I made privately were misconstrued. This added to my sense of tragedy and of those who are around me, including my family and friends.”

He added: “Despite these challenging times, what is required is to renew our faith and conviction and to stand together in unity with all parts of our community to send out a clear message that violence and intolerance of any kind will not be accepted within our communities. I’ve always been and will continue in my efforts to promote peace and harmony and to denounce any form of hate crime, radicalisation or extremism.”

Chief Superintendent Main said his officers would reach out to Mosques across Scotland ahead of Friday prayers.

“I’ve asked my colleagues across the country to ensure there’s engagement with all the Mosques ahead of Friday prayers to provide some reassuring messages but also to redouble the efforts around about our engagement to prevent radicalisation and extremism,” he added.