Updated at 10:42 a.m.

Virginia American Water said drivers should avoid the area around Route 1 at   North Henry and Montgomery streets for the next four to six hours because of an earlier water main break.

Crews are working to isolate the break, said Samantha Villegas, a spokeswoman for the water company. She said customers from First Street to Montgomery Street on North Henry Street, and on Montgomery Street from North Henry to North St. Asaph will be without water while repairs are made. She said the locations of which streets are without water may change, as crews continue to work to fix the leak.

Once the water main break is isolated, she said, one lane on North Henry — the far right lane — should be open for traffic.

Original post at 10:05 a.m.

Authorities said Wednesday morning that a major water main break is causing problems in Old Town Alexandria along Route 1.

One lane is closed on northbound Route 1 at Montgomery Street. Also the southbound lanes of Route 1 at Henry Street are closed because of the break.

Traffic is being diverted around the area.