A powerful tropical cyclone struck the southern Bangladesh coast on Thursday forcing hundreds of thousands of people to leave their homes after peripheral winds sparked giant waves and floods on offshore islands, officials said according to DPA. Up to 1 million people living in fragile coastal villages in the path of Cyclone Sidr were evacuated to safe locations as forecasters warned of hurricane-strength storms battering the coast at speeds of up to 200 kilometres per hour. "We have evacuated a million people to cyclone shelters since late Wednesday when the storm seemed headed for Bangladesh," said Muhammad Imam Mia, director of the disaster management office. Mia said that his office had a target of evacuating all families on the vulnerable coastline by early Friday. Interior ministry officials said over 50,000 Red Cross volunteers and members of civil defence groups were put on alert ahead of Sidr making landfall. A red alert was also sounded as the country's interim government closed domestic airports, seaports and ferry stations in southern Bangladesh. Senior Interior Ministry official Abdul Karim said more than 100 tourists were trapped on the coral island of St Martins, 30 km from the coast. Speaking during a meeting to coordinate rescue operations, Karim also said that helicopters were being used to search for survivors in the turbulent waters of the Bay of Bengal. Rescuers evacuated people from the islands to cyclone shelters to protect them against tidal flooding in the bay. Aid workers using megaphones warned people in remote fishing hamlets about the upcoming disaster. The main seaport in the business hub Chittagong hoisted danger signal number 10, indicating high emergency conditions. About 20 million people in 15 coastal districts are threatened by the disaster. More than 100,000 people were killed in the worst cyclone to hti the Bangladesh coast, in 1991. Earlier reports said the cyclone dumped heavy rains on the southern Bangladesh coastline of Khulna-Barisal triggering flash floods.