U.S. President Barack Obama is urging tens of millions of people living in the projected path of Hurricane Irene to take precautions from what he says is likely to be a "historic" storm.
The president made a brief statement while vacationing on the island of Martha's Vineyard, off the coast of the northeast state of Massachusetts.
The skies were still blue over the island, but Hurricane Irene's forward bands were already touching the U.S. coast farther south in North Carolina. The central area of the storm, hundreds of kilometers out to sea, clocked winds of more than 160 kilometers an hour.
Obama said he wanted to give the public an overview of what he said is "likely to be a dangerous and costly storm."
"All indications point to this being a historic hurricane."
The president said federal agencies are preparing and supporting state and local emergency response efforts. He said the danger is such that an aircraft carrier group had been ordered out to sea to avoid the oncoming storm.
An estimated 65 million people live in Irene's projected path. Obama urged them to take the threat seriously and not wait or delay.
"I cannot stress this highly enough: If you are in the projected path of this hurricane, you have to take precautions now," he said.
The president said residents should evacuate if told to do so.
Earlier Friday, Homeland Security Secretary Janet Napolitano also issued a warning.
"This is a serious hurricane. It has already caused significant damage in Puerto Rico and elsewhere. We are taking this storm very seriously, and I know that our state and local partners are as well," said Napolitano.
The main thrust of the storm is expected on Saturday, moving up the coast toward Washington, New York and New England. Damage estimates are projected to run into the billions of dollars.