NEW YORK (Reuters) - The U.S. National Guard rescued 21 people trapped at a Catskill Mountains motel and campground on Sunday following flooding triggered by Hurricane Irene, authorities said.

Residents of Moore's Motel and Resort in the small Catskills community of Prattsville became stranded after fast-moving water flooded much of surrounding Greene County, blowing out bridges and roadways.

There were no reports of deaths or injuries at the motel, which has an adjoining campground and trailer park. But the deep water made it difficult for rescuers to reach the property, said Shaun Groden, Greene County administrator.

"This is historical in terms of previous storms we have experienced," Groden said.

He said the National Guard ground crews were ultimately able to "punch through" and rescue the stranded residents.

Helicopters had earlier been dispatched to the area when roads were found flooded, but their efforts to rescue the motel residents were hampered by low cloud ceilings and 40 to 50 mile-per-hour crosswinds.

Rescue crews had also been unable to reach the motel using boats after finding the rivers were too swift.

Groden said there were also people reported stranded elsewhere in Greene County, which has about 50,000 residents and is located some 30 minutes south of Albany by car.

"We've had some major blowouts of bridges and roadways," he said. "We have isolated pockets and roadways where we have no ability to drive to them."

During a briefing for reporters on the effects of Hurricane Irene, New York Governor Andrew Cuomo said Greene County was among those for which he had sought a federal disaster declaration.

"We have tremendous flooding in upstate New York, in the mid-Hudson area and the Catskill area," Cuomo said.

(Reporting by Eric Johnson and Dan Whitcomb; Editing by Cynthia Johnston)