Iranian and US negotiating teams are due in Doha but Iran says no meeting has been scheduled as weekend missile fire from both sides tested the interim ceasefire to end the four-month-old war.
US President Donald Trump is sending son-in-law Jared Kushner and envoy Steve Witkoff to lead the negotiating team.
While Iran is sending its technical delegation to Qatar this week, foreign ministry spokesperson Esmaeil Baghaei said it had "no relation" to the Americans' visit and no talks between the two sides were scheduled.
"We will not have any negotiation meetings at any level with the American side in the coming days," Baghaei said.
The disagreement over whether the sides would even meet underscored the fragility of a June 17 accord to pause a conflict that has disrupted global oil flows through the Strait of Hormuz and created a political headache for Trump ahead of November's congressional elections.
Iran has rejected international involvement in mine clearance in the Strait of Hormuz, proposed by French President Emmanuel Macron, Deputy Foreign Minister Kazem Gharibabadi wrote on X.
Such a deployment would violate the existing framework agreement, he said. The accord stipulated that responsibility for mine clearance lay exclusively with Iran, he said.
Tehran would never allow a joint operation, he said, accusing Paris of aggravating the tense situation in the Gulf.
"We strongly advise France not to complicate it further with its provocations," he wrote.
Macron discussed the Strait of Hormuz during a visit by the Sultan of Oman, Haitham bin Tarik, to Paris.
"We have decided to collaborate jointly, in co-ordination with our partners, on demining the strait to secure maritime routes and ensure free and unconditional passage through the Strait of Hormuz," Macron wrote on X after the meeting.
The US and Iran gave themselves at least 60 days to implement the 14-point memorandum of understanding to extend an April ceasefire, discuss Iran's nuclear program and negotiate a permanent truce. But progress has been halting, with each side accusing the other of violating agreed terms.
Israel has not joined the US-Iran peace talks and has distanced itself from the agreement.
Tensions between Washington and Tehran have complicated efforts to end fighting in Lebanon, where Parliament Speaker Nabih Berri, an ally of Iran-backed Hezbollah, has cast doubt on a separate, US-brokered agreement between Lebanon and Israel aimed at halting the conflict.
Closure of the waterway sent oil prices to above $US100 ($A145) a barrel, pushing up global inflation and putting pressure on Trump ahead of the mid-term elections that will determine control of the US Congress.
A senior Iranian official said there would be a meeting in Doha on Tuesday but unlike previous technical talks between Iran and US teams in Switzerland, the focus would be on managing the Strait of Hormuz and de-escalating tensions.
Another official said technical teams from the US and Iran were expected to meet separately with Qatari and Pakistani mediators on Wednesday.
Trump told reporters in the Oval Office, "the meeting in Doha is going to be perhaps important, perhaps not. We're going to find out".
At the same time he maintained "we're winning militarily" and repeated his condition that Iran must be stopped from producing a nuclear weapon.
Iran has sought leverage by flexing its control of the strait, saying it plans to charge fees to ships using the waterway and obstructing vessels that stray outside defined paths.
The US has accused Iran of hitting at least two commercial ships with missiles or drones in recent days and bombed Iranian military facilities in response.
Iran in turn launched missiles and drones at US military sites in Kuwait and Bahrain early on Sunday.
with dpa