Air India has received an e-mail warning of a terror attack after which security around establishments of the national carrier across the country has been beefed up.

"We received an e-mail last week which we passed on to the security agencies concerned. The Bureau of Civil Aviation has also issued an alert. On our part, we are taking all the required security measures," an Air India spokesperson said in Mumbai on Saturday.

The airline had received a similar e-mail in April, threatening to blow up its headquarters at Nariman Point in Mumbai.

"I am not aware about any such threat. Air India has so far not communicated to us on the issue. However, we monitor security measures on a regular basis," Deputy Police Commissioner, Brijesh Singh, said.