WASHINGTON: A loud sonic boom alarmed people in the US capital on Sunday as F-16 fighter jets scrambled at supersonic speed to intercept a jet that had entered the no-fly zone around Washington.

Within minutes, the plane, which was not responding to warnings from the F-16s, crashed in Northern Virginia, killing the pilot and three others.

On Monday, the US media reported the victims were family members of a leading Republican who supports former president Donald Trump.

John Rumpel, a Florida businessman, later said his daughter Adina Azarian, 49, and two-year-old granddaughter were among the four victims.

Mr Rumpel, owner of Encore Motors franchise, said his company owned the Cessna Citation twin-engine jet, which crashed near Mon­tebello, Virginia.

“It descended at 20,000 feet a minute, and nobody could survive a crash from that speed,” he said.

“They all just would have gone to sleep and never woke up,” Mr Rum­pel told the New York Times in a brief interview.

The incident caused a security scare in Washington as the unresponsive plane was flying over a restricted airspace. After 9/11, the US government created a no-fly zone in and around Washington, which extends approximately 24km to 28km.

But the US media reports suggested that the plane was not responding to warnings from the F-16s, because the pilot lost consciousness while flying from Tennessee to Long Island, New York. This caused the plane to stray into airspace over the US capital.

Norad said they scrambled two F-16 fighter jets to intercept the Cessna, but the F-16s did not shoot it down. The jets caused the sonic booms as they raced to catch up with the light aircraft. The booms, heard in Virginia and Maryland as well, caused a brief panic as some people interpreted it as another terrorist attack while others assumed the booms were caused by an earthquake.