Iranian Minister of Foreign Affairs Abbas Araghchi (Photo: Reuters)

He noted that Iran is evaluating if fruitful negotiations could be shaped at the time and location proposed for the next round of talks.

"We will stand against excessive demands at the negotiating table, but we have never abandoned diplomacy," Araghchi said, adding that (Uranium) enrichment will continue with or without an agreement.

Facilitated by Oman, Iranian and US delegations have so far held four rounds of indirect talks from April 12 to May 11 on Tehran's nuclear program and the lifting of US sanctions. The first three rounds were considered positive by both sides.

However, in recent days, US officials have repeatedly demanded that Iran completely cease uranium enrichment.