WASHINGTON, Jan 18: The Bush administration has imposed economic penalties on several Chinese companies because it says they helped Iran in its effort to improve its weapons programs, administration documents show.

The action is part of a campaign by the Bush administration to counter what it sees as Iran's pursuit of nuclear weapons and the missile systems to deliver them. Iran denies its nuclear facilities are to be used to make weapons.

The administration made no public announcement of the penalties, first reported by The New York Times on Tuesday. The penalties and the companies affected were disclosed in government documents published earlier this month.

US officials say the exports to Iran included high-performance metals, the Times said. A senior Bush administration official declined to discuss the details of the case, saying only: "We have had conversations with the Chinese government about our concerns about proliferation."

China on Tuesday said it stands opposed to any spread of weapons of mass destruction. "The US government has wantonly launched sanctions against Chinese companies without any evidence," Foreign Ministry spokesman Kong Quan told a news briefing in Beijing.

The penalties bar the companies from doing business with the US government and prevent them from obtaining export licenses allowing them to buy controlled technologies from American companies.

The Chinese companies on the penalties list include China Aero-Technology Import Export Corp; China Great Wall Industry Corp; and China North Industry Corp, also known as NORINCO. -Reuters