Russian spy agencies are mounting a disinformation campaign to kill public confidence in COVID-19 vaccines made in the West, a U.S. State Department official says.

The U.S. has identified four online publications that serve as fronts for Russia's intelligence operatives.

The department claims the publications' objectives are to undermine trust in COVID-19 vaccines produced by Moderna, Inc., Pfizer Inc. and other pharmaceutical companies based in the West.

The department's global engagement center identified New Eastern Outlook, News Front, Rebel Inside and Oriental Review as the Russian online publications spreading misinformation about the coronavirus and "international organizations, military conflicts, protests and any divisive issue that they can exploit," the U.S. official said.

"We can say these outlets are directly linked to Russian intelligence services," The Wall Street Journal, which first reported on the disinformation, quoted the department official as saying.

"They're all foreign-owned, based outside of the U.S...but they're all part of the Russian propaganda and disinformation ecosystem."

News Front is allegedly run by the Federal Security Service of the Russian Federation - the principal security agency of Russia and the main successor agency to the Soviet Union's KGB - and has ties to Kremlin funding, the department said. Oriental Review and New Eastern Outlook are directly controlled by the country's foreign intelligence agency.

A fourth organization, Rebel Inside, overseen by Russia's armed forces, was also identified by the department but is largely dormant, the official said.

Bret Schafer, an expert on disinformation and one of the report's authors, said the stakes are very high as nations like China and Russia compete to distribute their own vaccines to the developing world.

The U.S. and other countries are competing to immunize people using three vaccines developed by Pfizer, Moderna and Johnson & Johnson.

A Kremlin representative denied the U.S. accusation. Russia's embassy in Washington didn't respond.