The 31st anniversary of Operation Bluestar on Saturday went off peacefully amid tight security arrangements here even as SAD (Amritsar) supporters raised pro-Khalistan slogans at the Akal Takht. Supporters of Shiromani Akali Dal (Amritsar), led by former MP Dhian Singh Mand, assembled at Golden Temple and raised ‘Khalistan Zindabad’ slogans besides brandishing swords. As many as 25 Sikh youths were detained, police said. Tight security arrangements were made by Punjab police to prevent any untoward incident. Policemen in civil dress along with SGPC task force were present on premises of the Golden Temple, officials said.