U.S. officials said state-owned companies primarily from China but also from Belarus, North Korea, Russia and Ukraine have contributed to Iran's Shihab-3 intermediate missile program. They said the aid has been in the form of exports of missile components and expertise.

For the first time, officials said, a company in a NATO ally also sold missile and WMD components to Iran. That company was identified as being located in Spain.

On Sept. 29, the State Department imposed sanctions on 14 foreign firms and individuals regarding the sale of missile and WMD technology and equipment to Iran. Officials said seven of those sanctioned were from China.

So far, 23 foreign entities have been sanctioned under the Iran Nonproliferation Act, Middle East Newsline reported. The legislation was meant to halt the sale of cruise and ballistic missile equipment and expertise as well as WMD technology to Iran.

Officials acknowledge that sanctions have not stopped many of these companies from Iranian missile and WMD contracts. The Chinese state-owned North Industries Corp., or Norinco, has been sanctioned several times for selling missile and WMD components to Iran.

North Korea's Changgwang Sinyong Corp., a leading in missile proliferation in the Middle East, has also been sanctioned numerous times, including last week. Changgwang is the state arms export agency of Pyongyang.

No government was sanctioned despite the acknowledgement by officials that several of the companies cited by the State Department were state-owned.

Officials said the sanctions marked the most sweeping action by the State Department under the Iran Nonproliferation Act approved by Congress in 2000. They said the decision reflected concern by the Bush administration that Iran was rapidly completing its nuclear weapons as well as intermediate-range missile delivery systems.

"In many cases the imposition of successive sanctions, one on top of the other, the main effect is to extend the period of time that entity would be subject to sanctions for," State Department spokesman Richard Boucher said.

"But it is a requirement of law that we make these determinations, and impose sanctions. And somebody who has been doing something more recently deserves to suffer the consequences for a longer period of time."

Boucher did not identify the exports to Iran. He said the equipment comprised "items that have a potential of making a material contribution to weapons of mass destruction of cruise or ballistic missiles, items on U.S. national control lists for weapons of mass destruction or missile reasons."

Officials said the latest companies sanctioned reflected the range of suppliers to Iran's missile and WMD programs. In addition to the seven from China, the companies included two from India and one each from Belarus, Russia, North Korea, Spain and Ukraine. The sanctions were meant to prevent these companies or individuals from doing business with the U.S. government or buying U.S. advanced technology equipment for two years.

Spain's Telstar was also sanctioned under the latest decision by the State Department. Officials said Telstar was the first firm from a NATO ally to face such U.S. penalties under the Iran Nonproliferation Act.