(CNN) Iran's supreme leader has ordered preparations to begin to increase uranium enrichment, ramping up pressure on European states struggling to keep the Islamic Republic in a nuclear accord.

"The Atomic Energy Organization of Iran is duty-bound to prepare the ground for achieving 190 thousand SWUs," Supreme Leader Ayatollah Khamenei was quoted saying by Iranian state media, referring to a measure of uranium enrichment capacity.

He said that the increase would be "within the framework of the JCPOA for the time being," referring to the Joint Comprehensive Plan of Action, otherwise known as the Iran nuclear accord

Iran will inform the UN nuclear watchdog agency that preparations will begin on Tuesday, Behrouz Kamalvandi, spokesman for Iran's Atomic Energy Organization, was reported saying by state media.

"The leader [Khamenei] meant that we should accelerate some process ... linked to our nuclear work capacity to move forward faster in case needed," he added.

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