The U.S. Senate has expressed its support for President Bush's efforts to seek a diplomatic solution to the standoff over Iran's nuclear program, and voted down a proposal to impose sanctions on companies investing in Iranian energy development.
The Senate rejected by a 45 to 54 vote a measure that would have required the president to determine whether to apply sanctions against any company that invests in Iranian petroleum development.
The proposed amendment to the defense authorization bill aimed to cut off investment funds that could be used by Iran to acquire nuclear weapons.
A similar measure passed the House of Representatives in April.
Senator Rick Santorum, a Pennsylvania Republican, sponsored the failed Senate amendment.
"It is very important that we send a signal to companies and countries, that if they are going to continue to support this development within Iran, that there are going to be consequences to the country and to the company for continuing to do that," he said.
But the chairman of the Senate Armed Services Committee, Republican Senator John Warner of Virginia, said the measure could interfere with sensitive multilateral negotiations with Iran - talks that include the United States.
"The timing of this is unwise," he said.
Senator Joe Biden of Delaware, the top Democrat on the Senate Foreign Relations Committee, offered sharper criticism of the proposal, noting that the Bush administration opposes it.
"Mr. Santorum's amendment, in my view, and in the view of the Secretary of State, actually advocates a policy that would jeopardize President Bush's initiative and I believe play directly into the hands of Iranian hardliners," he said. "I think, if you read the language, it also has the potential to damage relations with some of the key countries whose cooperation we need to pressure Iran to abandon its nuclear ambitions."
Biden offered his own amendment expressing support for the Bush administration's diplomatic efforts to resolve the standoff with Iran.
The Senate passed the measure by unanimous vote.
A U.S.-European package of incentives has been offered to Iran to convince the government to end its nuclear enrichment program.
Iran says the program is intended only to produce energy, while the United States and Europe suspect Iran is trying to produce nuclear weapons.