The U.S. has imposed sanctions against the Russian state-run arms exporter, Rosoboronexport, in connection with the alleged proliferation of weapons of mass destruction.

Sanctions were also imposed on the same grounds against Venezuela, China, North and South Korea, the United Arab Emirates, Sudan, and Syria, as well as the Iranian Islamic Revolutionary Guards.

The sanctions are valid for two years and bar any U.S. aid, contracts or arms sales to the blacklisted entities.

The order was signed on October 16 and came into effect on Thursday.

A Rosoboronexport representative called the sanctions a "manifestation of unethical competition."

"We view the imposition of sanctions with regard to the sole Russian facilitator of arms sales as a manifestation of unethical competition," said Vyacheslav Davydenko.

In July and December 2006, the U.S. also imposed sanctions on Rosoboronexport for allegedly passing on equipment to Iran that could be used to develop weapons of mass destruction.