Iran will not hold talks with the United States "under any circumstances" while the rights of the Islamic republic are not respected, said an official quoted Thursday by state media.
"We have said clearly... as long as the rights of our nation are not satisfied, as long as words don't change into action, our path will stay the same as now," said Keyvan Khosravi, spokesman of the Supreme National Security Council.
"There will be no talks under any circumstances," he was quoted as saying by the official state news agency IRNA.
Mr Khosravi said there had been an uptick in official delegations travelling to Tehran from various capitals, although "most of them are coming on behalf of America".
"Without exception we have responded with the message of the Iranian nation's strength, reason and resistance" in line with the policies of the Islamic republic," he added.
Oman's Foreign Minister Yusef Bin Alavi arrived in Tehran on Monday followed by the German foreign ministry's political director Jens Plotner on Thursday.
Despite its efforts to isolate Iran, the United States said it welcomed the initiative and noted that Germany had diplomatic relations with Tehran.
"So we think that this is normal behaviour between two states. And we appreciate any efforts by the Germans to help de-escalate the situation," State Department spokeswoman Morgan Ortagus told reporters in Washington.
Oman played a crucial role in bringing Iranian and US negotiators together for preliminary talks that ultimately led to the 2015 Iran nuclear deal with major powers including the United States.
But US President Donald Trump withdrew from the deal in May 2018 and reimposed sanctions that had been lifted in exchange for Iran scaling back its nuclear programme.
With tensions between the two sides already high, there has been a dramatic escalation in recent weeks after the US labelled Iran's Revolutionary Guards as a "foreign terrorist organisation".
The United States also deployed a naval carrier group and B-52 bombers to the Middle East over unspecified alleged Iranian "threats" and the acting defence secretary, Patrick Shanahan, said Thursday that Washington may send more troops to the region.
Iran in turn rolled back parts of its commitments within the nuclear deal and gave an ultimatum to the remaining sides that more would follow if they did not provide relief from sanctions.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)