Hill residents were shaken last week by the boom of low-flying F-16s conducting training exercises over the Capitol and along the Potomac River.

“It was really loud,” said one staffer who lives on the Hill. “This was the first time I have really noticed it.”

The jets, operating under the direction of the North American Aerospace Defense Command, could be heard as far away as Fairfax County, Va., as what one resident described as a “dogfight” erupted in the air.

Marisa Grant, a Cassidy & Associates lobbyist who just moved to the Hill, at first didn’t know whether to be concerned. “I know [Ronald Reagan Washington] National Airport is not that near,” she said. But she added that since Sept. 11, 2001, she makes “a concerted effort to ignore” commotion because there’s so much police and military activity in the District.

NORAD announced May 19 that training flights would be conducted over the capital region from approximately 10:30 p.m. to midnight May 21, May 29 and June 4 and that F-16s would be “flying at low altitudes.”

“We had changed some of the flight profiles to minimize the noise” after the May 21 exercise, said Maj. Don Aria, chief of public affairs for the division of NORAD covering the continental United States.

The statement from NORAD headquarters at Peterson Air Force Base in Colorado said exercises of this nature have been conducted throughout the country for the past year and a half.

“For reasons of operational security NORAD will not discuss specific details of the exercises,” the statement read.