"We are ready to talk with every country within the framework of international regulations," Rohani, who currently heads the Iranian Expediency Council's Strategic Research Center, told reporters.
"If there are no preconditions, talks would be helpful and we could be hopeful of the results,"
The former Iranian top nuclear negotiator said expectations laid by the six world powers (the five permanent UN Security Council members plus Germany), are neither part of the international regulations nor among Iran's commitments.
Despite the rules enshrined in the Non-Proliferation Treaty (NPT) entitling every member state, including Iran, to the right of uranium enrichment, Tehran is now under three rounds of UN Security Council sanctions for turning down West's calls to give up its right of uranium enrichment.
Asked about France and Britain's concerns that their role in the 5+1 Group will fade away with the US joining nuclear talks, Rohani explained, "Regarding the nuclear issue, US does not intend to negotiate with us outside the 5+1 Group."
Meantime, the Iranian official confirmed that there may be separate negotiations between Tehran and Washington about other topics, saying, "Nothing has yet happened in this regard and these are mere slogans."
If there is a serious decision for talks it would be definitely influential on the atmosphere but the US is unlikely to start independent nuclear talks with Iran, he said.
In a clear indication of shift in Washington's policy on Iran under the new US administration, Secretary of State Hillary Clinton said in Brussels that Iran would be invited to attend a high-level conference on Afghanistan at the end of the month.
"There are a lot of reasons why Iran would be interested," she said. "So they will be invited. Obviously it is up to them to decide whether to come."