MOSCOW

Russian Foreign Minister Sergey Lavrov on Tuesday said that all parties involved in the Joint Comprehensive Plan of Action (JCPOA) -- known as the Iran nuclear deal – have an obligation to preserve it.

"If we talk about the need to preserve the JCPOA, it means that everyone, not just Iran, must fulfill the obligations," Lavrov said at a news conference in Moscow.

He said that Iran has exceeded the limit set on its low-enriched uranium stockpiles, because of the U.S. sanctions.

Lavrov added that the sanctions have effectively prevented Tehran, from selling the excess nuclear material.

Iran had acknowledged on Monday that it had exceeded the limit of stockpiles, set in the 2015 nuclear deal.

Lavrov said that Iran had voluntarily committed to limit its low-enriched uranium and heavy water stocks. But this obligation was inextricably linked to Iran's right to sell the surplus material.

Russia’s top diplomat also urged the EU to abide by its pledge and implement a working system, protecting trade with Iran from American sanctions.

Tensions have been running high between the U.S. and Iran since Washington unilaterally withdrew from a landmark 2015 nuclear deal last year. The agreement was an outcome of protracted negotiations between Tehran and the five permanent members of the UN Security Council, plus Germany and the EU.

The U.S. has since launched a diplomatic and economic campaign, to force Iran to renegotiate the deal.

Lavrov said as per the JCPOA, the EU has obligations to safeguard economic interests of Iran.

"I would very much like our European colleagues to fully realize their responsibility for the preservation of the JCPOA. They also have obligations under the agreement – to ensure the economic interests of Iran, including its ability to sell oil," he said.

Earlier, Iranian Foreign Minister Javad Zarif defended exceeding the limit of nuclear material stock.

Taking to Twitter, he said Iran did not violate the JCPOA, by exceeding the stock, referring to paragraph 36 of the agreement. “We triggered and exhausted para 36 of the JCPOA after the U.S. withdrawal,” he said. He also posted text of paragraph 36, which provides a mechanism to resolve disputes, when parties believe other signatories are not fulfilling their obligations.