Bangladesh has asked local authorities and two ports to raise their highest alert.

Authorities in Bangladesh have evacuated around 100,000 people from low-lying coastal villages and islands as Cyclone Bulbul crossed the coast of West Bengal with a maximum wind speed of 110-120 km per hour gusting upto 120 km per hour into Bangladesh.

"Severe cyclonic storm Bulbul crossed West Bengal coast close to Sundarban Dhanchi forest during 20:30 to 23:30 hrs IST of November 9 with the wind speed of 110-120 kmph gusting upto 135kmph," the India Meteorological Department (IMD) said early on Sunday.

The Bangladesh Meteorological Department has asked local authorities and two ports to raise their highest alert, as the cyclone is set to unleash a storm surge as high as two metres (seven feet) in coastal districts, Al Jazeera reported.

Bulbul is on course to make landfall in the southwestern Khulna region, near the Sundarbans, the world's largest mangrove forest, which straddles Bangladesh and part of eastern India and is home to the endangered Bengal tigers.

About 55,000 volunteers have been mobilised to go door-to-door and alert people about the storm.

Authorities have suspended a nationwide school test, cancelled the holidays of officials posted in coastal districts and called off a traditional fair that draws tens of thousands of people in the Sundarbans.

According to reports by Dhaka Tribune, State Minister for Disaster Management and Relief Dr Md Enamur Rahman has advised the people of 13 coastal districts to come to cyclone shelters by 2pm (local time).

The cyclone made landfall around 8.30 pm on Saturday 60 kilometres east of Sagar Island and 100 kilometres south of Kolkata and light to moderate rainfall is expected in the surrounding region, the IMD predicted.