WASHINGTON (Reuters) - Senators proposed further tightening sanctions on Iran on Wednesday, reflecting fears that companies overseas, particularly in China, are evading U.S. penalties imposed last year for doing business with Iran.
The bipartisan group said they want to step up pressure on Tehran to stop its suspected pursuit of nuclear weapons, highlighted by data this week from the U.N. nuclear watchdog.
The International Atomic Energy Agency revealed in a report fresh evidence that Iran has tried to weaponize its nuclear program.
The Senate bill was introduced a day after the Obama administration penalized seven foreign firms, including Venezuela's state-owned oil company, for trading with Iran.
The legislation is similar to a measure under consideration in the House of Representatives, making it more likely that some tightening of sanctions will pass in the current session of Congress ending in 2013.
The Senate version also targets the governments of North Korea and Syria with new sanctions.
"Congress should pass, and the administration should robustly enforce, strengthened sanctions against Iran to ensure that every effort is made to prevent Iran from threatening the United States and our allies in the region with nuclear weapons," Senator Susan Collins, a Republican co-sponsor of the bill, said in a statement.
Other sponsors include Democrats Robert Menendez and Bob Casey, Independent Joseph Lieberman and Republican Jon Kyl.
Iran says its uranium enrichment program is for generating peaceful nuclear energy, but the West suspects it is aimed at making a bomb.
The U.S. sanctions law passed last year tried to pressure Iran to drop its nuclear work by targeting its energy and banking sectors.
The new bill would strengthen that law by exposing joint business ventures with Iranian energy entities to sanctions, the senators said.
It also would require the State Department to respond to requests from lawmakers about sanctions investigations -- making clear that some think they aren't getting enough information.
And it would penalize any company that sells goods for military applications to Iran, North Korea or Syria, by freezing assets and denying access to the U.S. banking system.
On Tuesday the United States hit Venezuelan state oil company PDVSA with sanctions for supplying a gasoline blending component to Iran. Other companies sanctioned were from the United Arab Emirates, Singapore, Israel and Monaco.
(Editing by Xavier Briand)
Corrects Senator Jon Kyl's name in paragraph 8.