Some unknown persons vandalised the Mumbai Regional Congress Committee office at Azad Maidan here on Friday morning, a party official said.
The incident occurred around 8 am, when the cleaning work was underway and around half a dozen people suddenly barged inside.
Using sticks and other things they destroyed glass cabins, fittings and furniture in the office before leaving.
A team of Mumbai Police and senior party leaders have rushed to the spot to investigate and ascertain the people behind the attack.
There are no casualties in the incident though the office premises have been left badly damaged, a police officer said.