TEHRAN 

Iran said Monday it would break the internationally-agreed limit of enriched uranium stockpiles under the 2015 nuclear deal.

"We have already increased our [uranium] production in Natanz," Behrouz Kamalvandi, a spokesman for the Atomic Energy Organization of Iran (AEOI) said in statements cited by the official IRNA news agency.

"From today, the countdown has begun, and by June 27, our uranium production will have surpassed 300 kilograms,” he said.

Kamalvandi said Tehran is waiting for Iranian officials’ decision regarding starting the second stage of measures on reducing the nuclear deal-related commitments.

"Europeans still have time. We waited a year [for them to save the nuclear deal], which was our ‘strategic patience'," he said.

The spokesman said Iran has two options regarding uranium enrichment levels.

"One is to increase the enrichment up to 5% for the use in Bushehr power plants, or to increase it up to 20% for Tehran reactor," he said.

Kamalvandi said in case Tehran does not find a market within a period of 2.5 months, Iran’s stockpiles of heavy water could climb to 130 metric tons.

"This is an important test for Europe...it will be a detriment to them to let the U.S. make their decisions for them," he said.

Tensions have been rising between the U.S. and Iran since last year, when the U.S. unilaterally withdrew from the 2015 nuclear between Tehran and the five permanent members of the UN Security Council plus Germany.