The main commemorative function was held at Mumbai Police Gymkhana at Chowpatty where a 26/11 memorial has been erected.
Maharashtra Governor K Sankaranarayanan, Chief Minister Prithviraj Chavan, Union Home Minister Sushilkumar Shinde, Maharashtra Home Minister RR Patil, Mumbai Police Commissioner Satyapal Singh and others paid floral tributes to the victims and martyrs at the memorial on Monday morning.
Family members of security personnel who were killed, other victims of the terror attacks, some survivors and those who took part in the anti-terror operations also attended the memorial function.
Security has been beefed up across city for the fourth anniversary of the attacks which comes close on the heels of the hanging of lone caught terrorist Ajmal Amir Kasab.
Mumbai Police Commissioner Satyapal Singh said that even though there were no specific threats, the city was generally on high alert for the past week.
Meanwhile, a peace march was held in Mumbai on eve of 26/11 anniversary. Among those who participated in the march were Union Minister of State for HRD Shashi Tharoor, Bollywood actress Mahima Chaudhary and American national Kia Scherr who lost her husband Alan and daughter Naomi during the attack.
Commemoration events will also be held at Chhatrapati Shivaji Terminus, Taj Mahal Palace and Tower hotel, Hotel Trident, Leopold Cafe and Nariman House, which were targeted by the terrorists who sneaked into Mumbai through the Arabian Sea and landed at Colaba.
The terror attack that continued for 60 hours left 166 dead and nearly 300 injured.