WASHINGTON DC, UNITED STATES (REUTERS) - US President Donald Trump has directed the full resources of the federal government to help Florida and other states hit by Hurricane Irma and has "great concern" about the storm as it batters the Florida coast, his vice-president said on Sunday (Sept 10).

"Clearly the briefing that we received at Camp David this morning caused the president to have great concern for the impact of this storm moving up the west coast, and the potential through heavy winds and storm surge to compromise cities and compromise lives," Vice-President Mike Pence told reporters.

Pence made the comments during a visit to the Washington headquarters of the Federal Emergency Management Agency with treasury secretary Steven Mnuchin, Commerce secretary Wilbur Ross, attorney-general Jeff Sessions and Health and Human Services secretary Tom Price.

"Wherever Hurricane Irma goes, we'll be there first," Pence said. "We'll be there with resources and support, both to save lives and to help to recover and rebuild these states and these communities."

Trump, who is slated to return to the White House later on Sunday, huddled with his Cabinet on the weekend at Camp David, where he spoke to the governors of Florida, Alabama, Georgia, South Carolina and Tennessee by phone as the projected path of the hurricane moved away from the lower Florida Keys westward to the Gulf Coast and states to the north.

"The president's been monitoring this storm 24/7," Pence said, urging residents in Irma's path to heed warnings from local officials. "The people of South Florida, the people of the entire state should know: We are with you."

Trump also issued a disaster declaration for Puerto Rico on Sunday and expanded federal funds available to the US Virgin Islands in the aftermath of Irma, the White House said.