Shimla, March 13 (IANS): The opposition BJP, led by former chief minister Prem Kumar Dhumal, on Friday submitted a memorandum to Governor Kalyan Singh here demanding a CBI probe into the reported attack by Youth Congress activists on BJP's office here on January 29.

The office was attacked during a demonstration over the central government's land acquisition ordinance.

The BJP demanded dismissal of the government.

The BJP warned that if the state government failed to act by March 31 against those involved in the incident, the state assembly would be gheraoed.

In the memorandum, the BJP leaders said that following the attack on BJP's office the governor had summoned the police officials and had directed them to take appropriate action.

"But the very next day Chief Minister Virbhadra Singh not only gave clean chit to his son (Vikramaditya Singh) and Youth Congress workers but he also blamed BJP workers for this incident," it said.

Twelve activists of the Youth Congress and the Bharatiya Janata Yuva Morcha had suffered injuries in the clash.

Vikramaditya Singh had led the Youth Congress activists.