Yonathan Melaku, the Marine Reservist charged with shooting at military buildings in the D.C. region last fall, apparently tried to escape his jail cell by digging through a cinder-block wall, authorities said.

Members of the Loudoun County Sheriff’s Office discovered a small area of damage to the cinder block wall in Melaku’s cell on Friday, authorities said.

Kraig Troxell, the sheriff’s office spokesman, said the damage was “minimal” and there was no real threat of escape through the wall, which is reinforced with concrete.

Troxell said the incident was under investigation and declined to specify what instrument Melaku allegedly used to cause the damage.

In response to the apparent escape attempt, the detention center — where Melaku is currently held on grand larceny charges stemming from a rash of vehicle break-ins in Leesburg in May — was placed on lockdown Friday “only as a precaution,” according to authorities.

Melaku, an Alexandria resident, is also charged in federal court with shooting at five military sites across the region — including the National Museum of the Marine Corps and the Pentagon — between Oct. 16 and Nov. 2, 2010.