While Uber and Lyft fight for cab-calling supremacy, the two also have a common enemy: the state of Virginia. The state's Department of Motor Vehicles sent a cease and desist letter to both companies, ordering them to halt all operations in the state, the Washington Post reports.

Neither company plans to stop.

"As many of the current regulations surrounding taxis and limos were created before anything like Lyft's peer-to-peer model was ever imagined, we're committed to continuing to work with state officials to craft new rules for this new industry," Lyft spokeswoman Chelsea Wilson told Business Insider in an email statement.

She applauded the support and enthusiasm Lyft has received from Virginia customers and defended Lyft's services as being within regulations.

Uber spokeswoman Kaitlin Durkosh reacted similarly, telling Business Insider in an email that Uber has been working "in good faith with the DMV to create a regulatory framework for ridesharing." Durkosh said the DMV's actions will hurt thousands of small business entrepreneurs who depend on ride-sharing services across the state. Still, Durkosh said, "We look forward to continuing to work with the Virginia DMV to find a permanent home for ridesharing in the Commonwealth."

In his letters to the ride-sharing startups, DMV Commissioner Richard Holcomb wrote: "I am once again making it clear that Lyft/Uber must cease and desist operating in Virginia until it obtains proper authority."

Ealier this year, Commonwealth officials hit Lyft and Uber with more than $35,000 in civil penalties, the Post reports.

Interestingly, in nearby Washington, D.C., the D.C. Council is weighing legislation that would let ride-sharing apps operate freely as long as they fulfill certain requirements, the Post writes.