According to ABC affiliate WJLA-TV, the two vans were stolen from two diferent locations in Prince George's County, Virginia.
Police told WJLA the two U-Haul trucks contain Arizona license plates: AE10807 and AE15192.
Police are not treating the incident as terror-related, but a police source told the station "It just feels like something is going to happen."
KGO-TV SAN FRANCISCO, CA contributed to this report.