Unconfirmed accounts claim that a loud explosion was audible in the vicinity of Washington DC during US military air defense drills.

The DC Air National Guard allegedly conducted air defense drills over the Chesapeake Bay and was given permission to fly supersonic during an alert scramble exercise, according to a Twitter post by journalist Andrew Leyden.

A loud explosion was heard after 8 o’clock local time, according to residents of nearby Maryland and Virginia.

According to Tom Lynch of NBC, after hearing the noise cause windows to tremble and alarms to go off, panicked locals dialed 911 in a state of intense dread.

He tweeted: “Multiple people calling into News4 – and calling local 911 centers – reporting an explosion. Cause has not been found @nbcwashington”

Lynch later added: “Multiple local law enforcement agencies now believe the source of the explosion heard around Washington was a “sonic boom.” We’re awaiting a response from the DC Air National Guard.”

Reports indicate police are calling the Federal Aviation Administration to find out more.

Chief of Police for the City of Bowie in Maryland said on Twitter: “Reports of sounds of an explosion are coming into the communication centre.

“There has been no verified incident of any kind, and we are checking with other jurisdiction. We will update if further information is found.”

One Twitter user wrote: “Anyone else in Annapolis hear a big boom and then their house shake?”

It is currently unclear what caused the sound, but residents in both Annapolis and Dale City, Virgina, reported a strange sound. The two cities are around 60 miles apart.

“Something big just went boom in Manassas, VA,” another person added.

One person in the American capital even said they though a truck had hit their house.

They said: “Felt in in the eastern DC suburbs. Thought a truck hit my house.”