US Senate passed an Iran sanctions bill on Saturday that would impose mandatory sanctions on entities or countries that provide goods or services for Iran's weapons programs, US media reported.

After the adoption, Senate Majority Leader Bill Frist said the bill "strengthened one of our most important tools in the fight to keep nuclear weapons out of the mullahs' hands."

The bill was passed by voice vote and it was already cleared by the House of Representatives two days earlier. President George W. Bush is expected to sign it into law.

The United States has been sanctioning Iran since the takeover of the U.S. embassy in 1979 by Iranian radicals.

Moreover, the United States has been seeking to impose sanctions on Iran through the UN Security Council on the grounds that the Islamic country develops a nuclear weapon program under the cover of a civilian program. However, Iran has said that its nuclear program is for peaceful purposes only.