"In the event of failure, a military confrontation would appear to be almost inevitable," Jean-Noel Barrot said in parliament, adding that it would severely destabilise the region.

Earlier Wednesday, President Emmanuel Macron chaired a meeting on Iran.

US President Donald Trump has threatened that Iran will be bombed if it persists in developing nuclear weapons. Iran's supreme leader, Ayatollah Ali Khamenei, has promised to hit back.

"Our confidence and our conviction remain intact," Barrot said. "Iran must never acquire nuclear weapons."

"Our priority is to reach an agreement that verifiably and durably constrains the Iranian nuclear programme," he added.

Since taking office in January, Trump has reinstated his "maximum pressure" policy, which in his first term saw the United States withdraw from a landmark 2015 agreement on Iran's nuclear programme and reimpose sanctions on Tehran.

Western countries including the United States have long accused Iran of pursuing a nuclear weapon, which Tehran has denied, insisting that its enrichment activities are solely for peaceful purposes.

The 2015 nuclear deal between Tehran and world powers required Iran to limit its nuclear processing in exchange for sanctions relief.

- Complaint against Iran --

Barrot also announced that France would "soon" lodge a complaint against Iran at the International Court of Justice over the fate of two detained French nationals.

The complaint would be filed over "the violation of the right to consular protection", he said, referring to Cecile Kohler and Jacques Paris, who were detained in Iran in May 2022 on accusations of seeking to stir up labour protests.

Western countries have for years accused Iran of detaining their nationals on trumped-up charges in a policy of state hostage-taking to use them as bargaining chips to extract concessions.

"We are going to step up pressure on the Iranian regime even further," Barrot said.

He also said "additional European sanctions against Iranian officials responsible for the policy of state hostage-taking" would be announced in the coming days.

Cecile's sister Noemie Kohler praised the announcement, expressing hope that this will help "move the case forward."

"It is a major turning point, because Cecile and Jacques' fundamental rights have been violated from the start," she told AFP.

"This decision testifies to the mobilisation of France at the highest level," said Noemie Kohler.

Cecile Kohler's last spoke with her family in early March.

"It's very difficult for us because we have a feeling that she is starting to lose hope," her sister said.

In March, French national Olivier Grondeau, detained by Iran in 2022 on security charges but described by his family as an innocent tourist, was returned to France after being released.