The United States and European Union have cautiously welcomed Iran's offer to resume talks with world powers over its nuclear program.
At a joint press conference in Washington, Secretary of State Hillary Clinton and European Union foreign policy chief Catherine Ashton indicated that they were studying Iran's response to their proposal to restart stalled negotiations with the five permanent members of the UN Security Council and Germany.
"This response from the Iranian government is one we've been waiting for and, if we do proceed, it will have to be a sustained effort that can produce results," Clinton said.
Ashton suggested that Iran's overtures did offer some hope of an end to the impasse.
"There is a potential possibility that Iran may be ready to start talks," she said. "We'll continue to discuss and make sure that what we're looking at is substantive, but I'm cautious and I'm optimistic at the same time."
Clinton said if talks resume, Iran must promise to meet until it fully complies with its international obligations.
Working To 'Isolate' Syria
Clinton also addressed the situation in Syria, saying that the United States is working to "pressure and isolate" the regime of Bashar Al-Assad and help citizens caught in the government's deadly crackdown.
She maintained that Russia and China's recent veto of a UN Security Council resolution calling for Assad's resignation would not weaken the international community's resolve.
"President Assad should stand aside and should enable a process that would bring the people of Syria together, all of them -- an inclusive process that could take the country forward," she said.
The UN estimates that nearly 6,000 Syrians have died since the democratic uprising began almost one year ago.