Maritime ports of Mongla, and Chattogram-Cox's Bazar have been advised to lower local warning signal no. four but instead hoist danger signal numbers seven and six respectively as cyclone 'Amphan' approaches Bangladesh.
Coastal districts of Satkhira, Khulna, Bagerhat, Jhalokathi, Pirojpur, Borguna, Patuakhali, Bhola, Barishal, Laxmipur, Chandpur and their offshore islands and chars will come under danger signal number seven.
And coastal districts of Noakhali, Feni, Chattogram and Cox's Bazar and their offshore islands and chars will come under danger signal number 6.
In a special weather bulletin, the Met office on Monday gave the advices to the maritime ports.
It said the very severe cyclone storm 'Amphan' over southeast Bay and adjoining southwet Bay moved northwards and intensified over the west central Bay and adjoining south Bay.
At 3 pm, it was centered about 1075km south-southwest of Chattogram port, 1015km south-southwest of Cox's Bazar port, 985km south-southwest of Mongla port and 970km south-southwest of Payra port.
It is likely to intensify further and move in a northerly direction and then re-curve north-northeastwards and may cross Bangladesh coast between Khulna-Chattogram during late night May 19, the Met Office said.