Iran has announced it will raise its enrichment of uranium, breaking another limit of its 2015 nuclear deal with world powers.

Government spokesman Ali Rabiei told a news conference that Iran will go beyond the limit of 3.67% enrichment and that the new percentage “will be based on our needs”.

Iran made the decision a year after President Donald Trump unilaterally withdrew the US from the deal.

Iran has repeatedly warned Europe in recent weeks that it would begin walking away from an accord neutered by an American campaign of sanctions that blocked Tehran’s oil sales abroad and targeted its top officials.

The decision came less than a week after Iran acknowledged breaking the deal’s 300 kilogram limit on its low-enriched uranium stockpile.

Experts warn higher enrichment and a growing stockpile narrow the one-year window Iran would need to have enough material for an atomic bomb, something Iran denies it wants but the deal prevented.

In a last-minute diplomatic bid, French President Emmanuel Macron spoke to his Iranian counterpart, Hassan Rouhani, by phone, saying he is trying to find a way by July 15 to resume dialogue between Iran and Western partners.

Hopes for saving the faltering deal appear increasingly dim, as the Europeans have been unable to offer Iran any effective way around US sanctions. While the steps are concerning to nuclear non-proliferation experts, they could be easily reversible if Europeans offer Iran the sanctions relief it seeks.

Tensions began rising in May when the US rushed thousands of additional troops, an aircraft carrier, nuclear-capable B-52 bombers and advanced fighter jets to the Middle East.

Mysterious oil tanker blasts near the Strait of Hormuz, attacks by Iranian-backed rebels in Yemen on Saudi Arabia and Iran shooting down a US military drone have raised fears of a wider conflict engulfing a region crucial to global energy supplies.