The fire at MTNL building in Mumbai started around 3 pm and all those stranded were rescued.

The government on Tuesday ordered a high-level inquiry into the fire incidents in MTNL and BSNL buildings in Mumbai, Delhi and Kolkata, and asked the two firms to conduct fresh fire and safety audits in a time-bound manner.

"Two major fire incidents occurred at MTNL Bandra Telephone Exchange, Mumbai and in BSNL building at Salt Lake, Kolkata and one minor fire incident occurred in MTNL building at Kidwai Bhawan, New Delhi on July 22.

"While the cause of fire is being established by the Fire and Police departments, Minister for Communications...Ravi Shankar Prasad has ordered a high-level inquiry by BSNL/MTNL in relation to the said fire incidents," an official release said.

The fire outbreaks - which occurred in all these buildings on the same day - were controlled by the fire departments, and no casualties were reported.

The minister also asked Mahanagar Telephone Nigam Ltd (MTNL) and Bharat Sanchar Nigam Ltd (BSNL) to conduct fresh fire and safety audit of each of their buildings and installations in a time-bound manner.

Teams of experts from BSNL and MTNL have been deployed round the clock to ensure complete restoration of network and services at the affected premises.

The situation is being closely monitored at the highest level in both organisations, the release added.

A massive fire broke out on Monday in MTNL building in Mumbai trapping 84 people on the terrace of the nine-storey structure, all of whom were later rescued by fire brigade personnel in one of the biggest operations in recent times.

The blaze started at around 3 pm at the building in suburban Bandra, which houses state-owned MTNL, and all those stranded were rescued by the evening.

MTNL Bandra Telephone Exchange is a ground plus nine-floor building owned and used by the telecom company. The building houses two telephone exchanges with working telephone lines of about 25,000 in addition to administrative offices.

"The fire broke out at around 1500 hours on July 22, 2019 and was completely controlled by 03:00 AM on July 23, 2019. As reported by MTNL, the last fire audit of the building was conducted on July 12, 2018 and the building was found to be compliant. Land line services to about 25,000 customers and internet services of about 8,000 customers are down, which are likely to be restored within next four days," the statement said.

MTNL Kidwai Telephone Exchange in New Delhi is occupied by both the telecom PSUs. The building houses MTNL telephone exchanges and administrative offices of both the firms.

"The fire broke out at around 4 AM on July 22 and was completely brought under control by 7.45 AM. As reported by MTNL, the last fire audit of the building was conducted on May 27, 2019 and the building was found to be compliant. All telecom services from the premises are continuing unaffected by this fire incident," it added.

Mobile services linked to BSNL building at Salt Lake, Kolkata "were promptly restored", following a fire incident on July 22, while services to Andaman and Nicobar Islands and data services in West Bengal are likely to be restored in the next twenty-four hours, the statement said.