The US has said it hopes to resolve Iran's nuclear issue by gradually increasing the diplomatic pressures on Tehran.
"We have stated from the very beginning that we hope to resolve this issue diplomatically and have put ourselves on a pathway to gradually increase diplomatic pressure on the Iranian government," State Department spokesman, Sean McCormack said on Monday.
"We have shown that we have been patient in steadily increasing the diplomatic pressure. It is starting to have an effect on Iran, and the Iranian government," McCormack said, adding that the negotiation pathway is still out there for the Iranians.
US Secretary of State Condoleeza Rice has said that she is willing to meet Iranian officials on condition that Tehran suspends uranium enrichment activities.
Earlier Monday, Iranian President Mahmoud Ahmadinejad announced that Iran has begun enriching uranium with 3,000 centrifuges and is capable of enriching nuclear fuel "on an industrial scale." The US denounced the move.
The US has accused Iran of trying to develop nuclear weapons under the cover of a civilian nuclear program. Iran has denied the charges.