WASHINGTON - The Food and Drug Administration is warning doctors that a second counterfeit version of the best-selling cancer drug Avastin has been found in the U.S., packaged as the Turkish brand of the medication.

The FDA said in a posting late Tuesday that the counterfeits do not contain the active ingredient in Avastin. The vials are packaged as Altuzan, the Turkish version of Avastin that is not approved in the U.S.

Doctors bought the counterfeits through Richards Pharma, a distributor that also does business as Richards Services, Warwick Healthcare Solutions and Ban Dune Marketing Inc.

The agency is advising doctors to stop using any drugs acquired from the network.

In February the FDA announced an investigation into a different batch of fake Avastin distributed to doctors in several states.