More than three-fourth of the 100 Senators have urged US President Barack Obama to toughen sanctions on Iran until the country slows down its nuclear programme.
"Until we see a significant slowdown of Iran's nuclear activities, we believe our nation must toughen sanctions and reinforce the credibility of our option to use military force at the same time as we fully explore a diplomatic solution to our dispute with Iran," said a letter to Obama, signed by 76 Senators.
"We urge you (President) to bring a renewed sense of urgency to the process. We need to understand quickly whether Tehran is at last ready to negotiate seriously. Iran needs to understand that the time for diplomacy is nearing its end. We implore you to demand immediate serious moves on Iran's part," the Senators wrote.
The White House said the inauguration of the new President presents an opportunity for Iran to act quickly to resolve the international community's deep concerns over Iran's nuclear weapons program.
"Should this new government choose to engage substantively and seriously to meet its international obligations and find a peaceful solution to this issue it will find a willing partner in the United States," the White House Press Secretary, Jay Carney, told reporters.
Carney hoped that the new Iranian government will heed the will of the voters by making choices that will lead to a better life for the Iranian people.
In their letter, the Senators said Iran should move quickly toward compliance with United Nations Security Council resolutions demanding it suspended enrichment.
Iran must cease installing centrifuges, agree to the removal of 20 per cent enriched uranium, and cease work on the heavy water reactor being built in Arak.
