NEW DELHI, Nov. 12 (Xinhua) -- India's Meteorological Department (IMD) has issued a cyclone alert for southern states of Tamil Nadu, Puducherry and adjoining Andhra Pradesh coasts, officials said Monday.

According to officials, a deep depression in the Bay of Bengal has intensified into a cyclonic storm and is likely to cross the north Tamil Nadu and south Andhra Pradesh coast between Cuddalore and Sriharikota on Thursday.

"Cyclonic storm Gaja now lies at about 820 km east-northeast of Nagapattinam. It is expected to cross between Chennai and Nagapattinam during forenoon on Thursday," the IMD Chennai told media.

The IMD has already issued warnings about heavy rainfall and squally winds at most places over north coastal Tamil Nadu and adjoining coastal Andhra Pradesh.

The IMD said sea condition would remain rough to very rough over north Andaman sea and cautioned fishermen not to venture into Andaman Sea and adjacent west central Bay of Bengal.

"Sea will be very rough, fishermen are advised not to venture in the sea until Thursday," the officials said.

According to the IMD statement issued on Sunday, the storm was very likely to move west-northwestwards during the next 36 hours and then west-southwestwards towards north Tamil Nadu and south Andhra Pradesh coasts during the subsequent 48 hours.

The officials said gale wind speed reaching up to 110 kmph over west central and adjoining southwest Bay of Bengal is likely to cross north Tamil Nadu coast between Nagapattinam and Chennai on Thursday.