The men demanded cash from the tellers who turned over an undisclosed amount of money, Woolverton said.
The men left the bank and ran from the Wellington Giant Shopping Center. No shots were fired and no one was hurt, Woolverton said.
Patrol units arrived at the scene in response to the emergency call and cordoned off the area, but were unable to catch the robbers after searching the vicinity, Woolverton said.
Witnesses told police the men were wearing very dark clothes. One of the men was about 5 feet 9 inches tall and the other was 5 feet 11 inches tall. Witnesses said both men had heavy builds, Woolverton said.
Manassas police will be assisted in the investigation by special agents from the FBI, Woolverton said.
Anyone with information is asked to call Master Detective Luis DeRamos at (703) 257-8040, or call Crime Solvers at (703) 330-0330. Callers do not have to give their names or testify in court and may receive up to $1,000 reward for information that leads to arrest.
Anonymous tips may also be left at http://www.manassascity.org.pub_safety/crime.html, Woolverton said.
Staff writer Keith Walker can be reached at (703) 878-8063.