(Reuters) - The U.S. Food and Drug Administration said on Thursday it, along with international authorities, has formally sought to suspend 4,402 websites that illegally sell potentially dangerous, counterfeit or unapproved prescription drugs to U.S. consumers.

The move is part of a global effort being led by the INTERPOL, the world's largest police organization, to identify the makers and distributors of illegal prescription drugs.

The FDA said its Office of Criminal Investigations, Office of Regulatory Affairs, and Center for Drug Evaluation and Research were part of the enforcement action, which ran from May 31 to June 7. (http://1.usa.gov/1UDxltm)

The FDA and the U.S. Customs and Border Protection inspected international mail facilities (IMFs), and then sent formal complaints to domain registrars requesting the suspension of the 4,402 websites, the U.S. health regulator said.

In addition, the FDA said it has also issued warning letters to operators of 53 websites that illegally sell unapproved and misbranded prescription drug products to U.S. consumers.

The FDA said it and other federal agencies screened and seized illegal drug products received through IMFs in San Francisco, Chicago, and New York.

These screenings resulted in the detention of 797 parcels which, if found in violation of the Federal Food, Drug, and Cosmetic Act, will be refused entry into the country and destroyed, the FDA added.

Preliminary findings from these screening showed U.S. consumers had purchased certain unapproved drug products from abroad to treat depression, narcolepsy, high cholesterol, glaucoma, and asthma, among other conditions.

(Reporting by Natalie Grover in Bengaluru; Editing by Savio D'Souza)