Iran denied any negotiations were taking place with the United States after President Donald Trump said new talks would begin Monday in an effort to end their war, now in its sixth month.

The rebuttal by the Iranian foreign ministry follows Trump saying he had held off launching new strikes on the Islamic republic to allow for further diplomatic efforts, a familiar pattern in the conflict.

Washington and Tehran have been at war since 28 February, when the US and Israel launched surprise strikes against Iran, though months of on-off diplomacy have led to periods of relative calm.

Trump last week threatened to hit Iran “very hard”, with the US leader reportedly considering renewed attacks including against energy infrastructure.

But the president pulled back from that threat Saturday, saying the “perimeters” of a deal were there.

Iran’s foreign ministry however denied there were currently negotiations taking place.

“We are not currently negotiating with the United States. Our negotiations are with Oman to secure passage through the Strait of Hormuz,” said foreign ministry spokesman Esmaeil Baqaei during a weekly press briefing.

The Hormuz shipping route is a major sticking point in efforts to end the war. Iran has obstructed vessels attempting to pass the critical trade corridor, firing on commercial ships.

Before the war, there was free passage through the strait, but Iran now insists on retaining control and charging fees, something the US rejects.

Tehran has refused to let ships travel any route other than one which hugs the Iranian coast.

On Sunday, Baqaei told state television that a deal was close on managing Hormuz together with Oman, which sits on the other side of the narrow waterway.

“We are now going to reach an understanding on a route acceptable to both sides — neither the northern route nor the southern route — but one that respects the sovereign rights of both sides and safeguards our national interests and security,” he said.

But he insisted that such an agreement did not mean the reopening of the strait.

‘It begins tomorrow’

On Sunday, a tanker off the coast of Oman reported hearing an explosion nearby, the United Kingdom Maritime Trade Operations (UKMTO) Centre reported, but the ship and crew were all reported safe.

Trump told reporters on Sunday that the new talks with Iran would cover Hormuz and ultimately the denuclearisation of Iran.

The US president said at the start of the conflict that the war was necessary to deal with Iran’s nuclear programme. Western nations accuse Iran of seeking a bomb, though Tehran insists the programme is entirely civilian in nature.

“Now what we’re doing is we’re talking to them in the form of a negotiation. It begins tomorrow afternoon,” Trump told reporters aboard Air Force One on Sunday, without providing details of the venue or participants.

The president said he had been asked by Iran as well as US partners Saudi Arabia, the United Arab Emirates and Qatar to hold off on further strikes, which he claimed would have been “the biggest attack since World War II”.

Iranian media denied that Tehran had asked Trump not to strike.