The reason for the attack, which took place around 10.30 pm last night, is not known, police said, adding, remnants of the crude bombs were recovered from the spot.
There was no damage to property.
Condemning the attack, CPI-M State Secretary G Ramakrishnan said the party had been protesting against illegal mining of red sand which was going on in a large-scale in the area, besides encroachment in public places, and some political outfits were not happy about it.
The party's state executive urged police to immediately arrest those responsible for the attack.
