Hurricane Dorian pounded the Bahamas on Monday, killing at least five people and inundating homes with floodwater ahead of its expected advance on the U.S. coast, where more than a million people were ordered evacuated.

At least five people were killed in the Abaco Islands, in the northern Bahamas, Bahamian Prime Minister Hubert Minnis told a news conference on Monday. The U.S. Coast Guard transferred several of the injured from a clinic in Great Abaco Island’s Marsh Harbour in helicopter to a hospital in Nassau.

Dorian, one of the most powerful Atlantic hurricanes on record, had been hovering over Grand Bahama Island for 36 hours by early Monday evening and was expected to stay put until at least Tuesday morning, the Miami-based National Hurricane Center (NHC) said in its latest advisory.

It warned residents not to leave shelters until the eye of the hurricane passes. The storm’s strongest winds are usually close to the eye.