TEHRAN -- Spokesman for the Atomic Energy Organization of Iran (AEOI) said on Monday that Tehran plans to go back to the conditions before the landmark 2015 nuclear deal unless European signatories fulfill their obligations, state TV said.

Iran's retaliatory decision to reduce some of its commitments under the nuclear deal, the Joint Comprehensive Plan of Action (JCPOA), is within the framework of the accord which says if one side fails to deliver its commitments, the right is reserved for the other party to reconsider its obligations, said AEOI spokesman Behrouz Kamalvandi.

"If the Europeans and the United States do not fulfill their commitments, we will balance out their actions under the deal by reducing commitments and taking the conditions back to how they were four years ago," he said.

Iran and six world major powers sealed the landmark deal to end the controversies over the latter's nuclear program in 2015. Under the deal, Iran agreed to curb major parts of its sensitive nuclear program in return for the lift of UN as well as the western sanctions.

However, President Donald Trump has pulled Washington out of the deal and reinstated unprecedented sanctions against Tehran under the pretext of "flawed" nuclear deal and Iran's advancing ballistic missile program as well as its progressive influence in the region.

Since May this year, Iran has dropped some of its commitments subject to the deal and vowed to go further if its interests under the deal are not honored.

Kamalvandi said that Iran's uranium stockpile has surpassed 300 kg, the limit set by the deal, and Tehran is no longer obliged to export the surplus heavy water as it was required under the deal.

Besides, "currently, we have gone beyond 3.67 percent (uranium) enrichment purity and are also producing the enriched material required for nuclear plant fuel with 4.5-percent purity," he added.

The JCPOA was supposed to be an "exchange deal" but "what we give (within its framework) is way more than what we get in return," he concluded.