TEHRAN/DUBAI : Iran will exceed an agreed cap on its inventories of low-grade uranium in 10 days, potentially breaching for the first time a landmark 2015 agreement that was meant to prevent it from developing a nuclear bomb.

The spokesman for Iran’s atomic energy agency, Behrouz Kamalvandi, said the country would step up the pace of enrichment after that deadline. Crucially, Iran has not increased enrichment purity beyond a 3.67% cap set to prevent it from making weapons-grade uranium—but Kamalvandi hinted that it may do so.

“An important point, especially for the Europeans, to note is that actions taken in the first stage may have taken a while, but in terms of carrying out the next actions, especially enrichment beyond 3.67%, it won’t take that long," he said in a televised address, adding that Iran could enrich up to 20% for domestic uses.

The announcement is likely to stoke further friction with the US, which has accused the Islamic Republic of being behind a spate of attacks on oil tankers near the Strait of Hormuz shipping chokepoint. Iran has denied any wrongdoing.

Tensions in the Gulf have spiked since the US stopped granting waivers to buyers of Iranian oil in early May, tightening sanctions slapped on the Islamic Republic after President Donald Trump pulled the US out of the nuclear deal a year ago.

Iran responded by threatening on 8 May to gradually withdraw from the multilateral accord unless the remaining parties throw it an economic lifeline within a rapidly-approaching 60-day deadline. It said it would no longer comply with a 300-kilogram cap on the storage of enriched uranium and a 130-ton limit on stocks of heavy water imposed by the deal. The country has since accelerated four-fold the rate at which it is enriching low-grade uranium and said it could hit its cap on heavy water storage in two-and-a-half months.

Kamalvandi said European parties to the deal still had time to save it but the deadline would not be extended. If Europe gives the Iranians a way to maintain access to international oil and financial markets, Iran has promised to resume complying fully.

An Iranian violation will turn up the heat on diplomats and monitors at the International Atomic Energy Agency responsible for monitoring compliance. IAEA Director General Yukiya Amano confirmed Iran had raised its rate of production last week and warned the nuclear deal was coming under “increasing tensions."

Inspectors are on the ground daily in Iran and any violation will be reported to IAEA members, Amano said. Overstepping stockpile limits could result in an extraordinary meeting of the IAEA’s board and the start a process that could lead to the re-imposition of broader United Nations sanctions.

Iran has said it is not seeking to develop a nuclear weapon.

Meanwhile, a White House National Security Council spokesman has said that Iran’s plan to exceed internationally agreed curbs on its stock of low-enriched uranium amount to “nuclear blackmail" and must be met with increased international pressure. “Iran’s...plans are only possible because the horrible nuclear deal left their capabilities intact," NSC spokesman Garrett Marquis said.

“President Trump has made it clear that he will never allow Iran to develop nuclear weapons. The regime’s nuclear blackmail must be met with increased international pressure," he added.bloomberg

Reuters contributed to this story.