The deep depression over the Bay of Bengal intensified into Cyclone Yaas in the early hours of Monday and it is likely to intensify into a severe cyclonic storm in the next 24 hours, the India Meteorological Department said.
The cyclone is very likely to cross north Odisha-West Bengal coasts between Paradip and Sagar Island around May 26 noon as a 'very severe cyclonic storm'. It is expected to bring in winds of 155 to 165 kilometres per hour, gusting up to 180 kmph.
"It (Cyclone Yaas) is very likely to move slowly north-northwestwards, intensify further into a Severe Cyclonic Storm during next 24 hours and into a Very Severe Cyclonic Storm during subsequent 24 hours," the Cyclone Warning Division of the IMD said.
The West Bengal and Odisha governments have been bracing to deal with the impact of the cyclone.
On Sunday, Prime Minister Narendra Modi chaired a high-level meeting to review the preparedness of the state and central agencies to deal with the situation, and called for a timely evacuation of those involved in offshore activities.
The armed forces are also on alert, with the Navy putting four warships and a number of aircraft on standby.
The Air Force has kept 11 transport aircraft and 25 helicopters ready to carry out humanitarian assistance and disaster relief operations, officials said.
National Disaster Response Force chief S N Pradhan has urged authorities in the two states to adopt an "over-preparing" approach for the impending natural disaster, and carry out evacuation even in the least vulnerable places.