(CBS/AP)  WASHINGTON - The Secret Service says a bullet hit an exterior window of the White House and was stopped by ballistic glass.  An

additional round of ammunition was also found on the exterior of the White House. The bullets were found Tuesday.  The discovery follows reports of gunfire near the White House on Friday. Witnesses heard shots and saw two speeding vehicles in the area. An AK-47 rifle was also recovered.

The Secret Service says it has not conclusively connected Friday's incident with the bullets found on the White House grounds. U.S. Park Police have an arrest warrant out for Oscar Ortega-Hernandez (shown below), who is believed to be connected to the earlier incident.

A statement from the Secret Service confirmed that the Secret Service, Park Police, FBI, ATF and Metropolitan Police Department were working together to find Ortega-Hernandez. 

A vehicle found on Friday between the Ellipse and the Washington Monument - an area just 700 or 800 yards from the White House, led authorities to issue the arrest warrant for the man, who is described as a "21-year old, Hispanic male, 5'11", 160 pounds, with a medium build, brown eyes and black hair."