Iran's Foreign Minister Abbas Araghchi says a potential resumption of war with Israel and the United States would not change his country's positions.
The remarks on Sunday came amid mounting US and Israeli threats of renewed attacks on Iran.
US President Donald Trump said on Friday that Washington "may do another little Epic Fury," referring to the US-Israeli campaign on Iran that began on February 28.
Mr Araghchi said a fresh attack would not yield a different outcome.
"Recently, there has been talk of a new war, but I am already thinking about the post-war period. Whether there is war or not, our policies remain the same," Mr Araghchi said during a televised event in Tehran.
"They have already done so twice and have seen the results. If they want to try again, they know they will achieve no different outcome from those of the past."
A plume of smoke rises after a US strike in Tehran in March. (AP: Vahid Salemi)
An April 8 ceasefire between Iran and the US put an end to the most intense fighting, apart from sporadic exchanges of fire in and around the strategic Strait of Hormuz, a key route for global energy supplies.
These military flare-ups have lulled in recent weeks.
Iran has claimed control over the strait since the outbreak of the war and has regularly targeted vessels that attempt crossing without its authorisation, moves strongly opposed by Washington and countries in the region.
In response, the US has been maintaining a naval counter-blockade on Iranian ports.
In June, Iran agreed with the US to a memorandum of understanding laying out a pathway to a permanent settlement of the conflict, only for the deal to later unravel as each side accused the other of violating it.
Tehran has since called for a return to the accord to end the conflict.
"The current war has changed everything," Mr Araghchi said.
"We must accept that new realities are taking hold. Shipping routes through the Strait of Hormuz will no longer be the same, and the management of the strait will no longer be the same.
"To achieve peace and stability, our region must move towards the complete absence of foreign forces."
Ten ballistic missiles intercepted over Riyadh
The Houthis have warned they could again target Saudi Arabia, with Riyadh's airport "a military target". (Reuters: Mohammed al-Mahdi)
Meanwhile, Saudi Arabia intercepted drones and missiles over its capital Riyadh and southern areas on Sunday, the Saudi-led coalition in Yemen said, as fighting with the Iran-aligned Houthis persisted.
The conflict has become an increasingly destabilising front in the US-Israeli offensive against Iran, turning US ally Saudi Arabia into a pressure point in the wider war.
On Sunday, Saudi civil defence authorities issued emergency alerts for Riyadh, Abha and Khamis Mushait, before announcing minutes later that the danger had passed.
The coalition said two drones and a ballistic missile were launched towards Riyadh, and a cruise missile towards the southern city of Khamis Mushait.
Travellers were told that the King Khalid International Airport was again operating normally. (AP Photo)
It later said it intercepted 10 ballistic missiles fired towards southern Saudi Arabia.
The Houthis warned they could again target Riyadh's King Khalid International Airport, which resumed operations at two terminals on Sunday after a deadly attack earlier this month.
The Houthis said they attacked the airport and Saudi oil facilities on Saturday. Saudi authorities did not comment directly on the Houthi statements.
Houthi military spokesperson Yahya Saree said the airport remained a "military target" and warned all airlines, airport staffers and travellers against using it.
Wires/ABC