"The continuation of these illegal behaviours will not change Iran's logical, legitimate and international law-based positions," a foreign ministry statement said, condemning what it called "pressure on Iran's trade and economic partners".

It added that such sanctions have created "deep suspicion and mistrust about the seriousness of America on the path of diplomacy".

On Thursday, Trump vowed to enforce sanctions and called for a global boycott of "any amount" of Iranian oil or petrochemicals.

"All purchases of Iranian Oil, or Petrochemical products, must stop, NOW!" Trump wrote on his Truth Social platform.

"Any Country or person who buys ANY AMOUNT of OIL or PETROCHEMICALS from Iran will be subject to, immediately, Secondary Sanctions," he added.

His remarks came after Iran confirmed the postponement of the next round of nuclear talks with the United States, which had been expected to be held on Saturday, with mediator Oman citing "logistical reasons".

Oman said the date for a new round "will be announced when mutually agreed".

- 'Just and balanced deal' -

Foreign Minister Abbas Araghchi, who headed the Iranian delegation in the three rounds of talks held so far, said Iran was ready for a "just and balanced deal".

"There is no change in our determination to secure a negotiated solution," Araghchi said on X, adding that any deal should guarantee "an end to sanctions."

The talks mark the highest-level contact on Iran's nuclear programme since Trump abandoned a landmark accord between Tehran and major powers in 2018.

The US president had written to Iran's supreme leader Ayatollah Ali Khamenei in March urging negotiations but warning of potential military action if they failed.

Since returning to office in January, Trump has revived his "maximum pressure" policy of sanctions against Iran, with the latest announced on Wednesday and targeting seven companies accused of transporting Iranian-origin petroleum products.

Tensions over Iran's nuclear programme soared after Washington withdrew from the 2015 deal with major powers which offered Tehran sanctions relief in return for restrictions on its nuclear activities.

Iran adhered to the agreement for another year before beginning to roll back its compliance.

Western governments have since accused Tehran of seeking a nuclear weapons capability, an ambition it has consistently denied, insisting that its nuclear programme is for peaceful purposes only.

On Monday, French Foreign Minister Jean-Noel Barrot said Iran was "on the verge of acquiring nuclear weapons".

He also warned that UN sanctions against Tehran -- lifted under the 2015 nuclear deal -- could be reimposed if Iran's nuclear activities were seen to threaten European security.

Iranian foreign ministry spokesman Esmaeil Baqaei said the French foreign minister's remarks were "simply absurd".

"This false statement, coupled with the minister's open threats to reimpose sanctions, reinforces the suspicion that France's nagging posture risks evolving into a spoiling role."