Over 2,500 people have been evacuated from St Martin's Island so far.
Being the most dangerous area to face the wrath of the cyclone Mocha, they were moved to safety shelters in Teknaf and nearby areas, Cox's Bazar District Relief and Rehabilitation sources said.
"Under the peripheral effect of the cyclone, there is a risk of inundation of the low-lying areas," Md Jahangir Alam, an official of Cox's Bazar Relief and Rehabilitation Centre, told BSS.
"The work of moving people to safety started this morning. People in Moheshkhali's Matarbari and Dhalghata, Shahparir Dwip in Teknaf and St Martin's Island have taken refuge in nearby safety centers. The administration is providing cooked and dry food to the sheltered people at various centres," he added.
A control room has been opened in Cox's Bazar District Commissioner Office with a hotline -- 01872615132.
The district administration sources said that 576 shelters have been opened in the district since this morning. Miking campaign is being carried out to make the coastal residents take shelter before the cyclone hits.
Deputy Commissioner of Cox's Bazar Muhammad Shahin Imran said: "Apart from the 576 shelter centres, various social, educational and religious institutions have been prepared as temporary shelters for more than five lakh people."
Around 8,600 volunteers of the Red Crescent are campaigning for people to come to the shelters and the administration is providing vehicles for a speedy evacuation, he added.
"Around Tk 10 lakh in cash, 440 tonnes of rice, seven tonnes of dry food, ample amount of water purification pills and 194 bundles of corrugated tin have been kept as emergency relief supply," the DC said.
Hundreds of people have taken shelter in Municipal Preparatory High School of Cox's Bazar Sadar as the weather forecast predicted that the cyclone may start from this evening.
The district Administration has marked out the highly perilous areas, which are prone to tidal surge, flooding and land slide or mountain collapse due to heavy rain. Therefore, people are being evacuated to the shelters from the dangerous areas, the DC added.
The local meteorological department in its latest directives asked the seaport of Cox's Bazar to hoist Great Danger Signal No 10 and all fishing boats and trawlers over north bay and deep sea have been advised to remain in shelter till further notice.