Washington, Oct 6 (IANS): US President Barack Obama warned that hurricane Matthew could have a devastating effect, as residents of the southeastern coastline braced themselves for one of the most powerful storms to hit the region in almost a decade.

"This is a serious storm," said Obama on Wednesday after visiting the Federal Emergency Management Agency headquarters.

"Even if you don't get the full force of the hurricane, we are still going to be seeing tropical force winds, the potential for storm surge, and all of that could have a devastating effect," he added.

According to the US National Hurricane Center, the deadly Category 3 hurricane was roughly 105 miles, or 169 km, south of Long Island in the Bahamas on Wednesday, Xinhua news agency reported.

"We anticipate that by tomorrow (Thursday) morning, it will already begin to have significant effect in Florida, and then ... potential(ly) ... strengthen and move on up the coast ...," said Obama.

In its preparation, the US states of South Carolina, Georgia and Florida started evacuation of over two million residents from its coastal areas and urged them to stock food, water and medicine for at least upto three days.