WASHINGTON: The US Secret Service says it has found a bullet that hit an exterior window of the White House and was stopped by ballistic glass.

An additional round of ammunition was found on the White House exterior. The bullets were found on Tuesday morning.

A spokesman for the Secret Service, Edwin Donovan, declined to answer additional questions about the incident, including the caliber of bullets recovered or what room of the White House was behind the window that was hit, citing an ongoing criminal investigation.

The discovery follows reports of gunfire near the White House on Friday. Witnesses heard shots and saw two speeding vehicles in the area. An assault rifle was recovered.

President Barack Obama, who was headed to a summit in Hawaii, was not at the home at the time of the shooting.

The Secret Service said it has not conclusively connected Friday's incident with the bullets found at the White House. Previously, authorities had said the White House did not appear to have been targeted on Friday night.

US Park Police have an arrest warrant for Oscar Ortega-Hernandez, who is believed to be connected to the earlier incident.

After the gunfire was reported, police said they found an abandoned car Friday night near the Theodore Roosevelt Bridge that crosses the Potomac River to Virginia.

US Park Police spokesman Sgt. David Schlosser has said items found in the vehicle led investigators to Ortega. The suspect hasn't been linked to any radical organisations but does have an arrest record in three states, Schlosser said on Monday.

In 2010, there were a series of pre-dawn shootings at military buildings in the Washington area, including the Pentagon and the National Museum of the Marine Corps. Police charged a Marine Corps reservist with those shootings earlier this year. The suspect, Yonathan Melaku, remains in custody.—AP