Three persons, allegedly belonging to a fundamentalist group, have been arrested in connection with the Ghatkopar bomb blast, Mumbai Police Commissioner M N Singh said on Tuesday.

Singh, however, refused to name the fundamentalist outfit but said the same group was behind the December 6 explosion at an eatery in Mumbai Central railway station and the planting of explosives in a bus at the SEEPZ bus depot in Andheri. The explosives were found hours after the Ghatkopar blast.

The explosives used in these incidents were of low and medium intensity, he said.

He ruled out the involvement of Pakistan's Inter-Services Intelligence or Naxalites in these incidents.

"It is improper to name the ISI in every explosion that takes place in the city," Singh told reporters after delivering a speech on 'Role of the Mumbai police in complementing the social responsibilities of corporate citizens'.

He reiterated that the police is on a high alert to foil any attempt by terrorists to disrupt the peace in the metropolis.

More reports from Maharashtra