Iran's Foreign Minister Abbas Araghchi said there were no negotiations with the United States and that Tehran had not responded to a reported 15-point proposal from Washington to end the war.
"We receive messages from the American side, some direct and some through our friends in the region, and whenever necessary we respond to these messages," Araghchi said in an interview with Al Jazeera aired on Wednesday and dubbed into Arabic from Persian.
"There are no grounds for negotiations," he said, adding however that some messages had been exchanged directly with US special envoy Steve Witkoff.
Iran has been at war with the United States and Israel since February 28, when strikes killed the country's supreme leader and triggered a conflict that has spread across the region.
Diplomatic efforts involving Türkiye, Egypt and Pakistan have recently been launched to try to end the war.
Last week, two senior Pakistani officials said Islamabad had conveyed to Iran a 15-point plan containing US proposals.
Iranian media had reported that Tehran offered a five-point counterproposal calling for an end to what it described as "aggression" and for guarantees that neither the United States nor Israel would resume hostilities.
Araghchi, however, said Tehran "has not offered anything in response" to the US plan and that reported Iranian responses were "merely guesses" from a media outlet.
The war broke out in the middle of negotiations between Iran and the United States over Tehran's nuclear program.
The conflict echoes a 12-day war in June last year, when Israel launched strikes days before a planned round of talks between Tehran and Washington. The United States later joined those attacks, targeting Iranian nuclear facilities.
Araghchi said there was "zero" trust in the United States and that Iran would not accept a ceasefire, instead calling for a "complete end to the war" and reparations.
Since the start of the conflict, now in its second month, Iran has allowed only a trickle of ships to pass through the strategic Strait of Hormuz, disrupting roughly 20 percent of global oil flows.
Iran says the strait is closed to what it describes as "enemy" shipping.
In recent days, Iranian officials have said the US may be plotting a ground attack with the arrival in the region of the USS Tripoli, an amphibious assault ship carrying around 3,500 Marines and sailors.
Araghchi warned that "we are waiting for them... they will incur heavy losses".
