Iran's president says increased uranium enrichment will begin in 60 days if world powers don't shield it from U.S. sanctions, under the terms of the 2015 nuclear agreement.

The news comes exactly one year after President Trump pulled the U.S. out of the agreement, calling it "a horrible one-sided deal." In August, the Trump administration restored some of the sanctions that were lifted as part of the 2015 nuclear deal.

President Hassan Rouhani announced on Wednesday that Tehran will start keeping larger amounts of enriched uranium and heavy water, instead of selling the excess to other countries, as the deal requires.

And he said that if the other countries in the accord haven't figured out a way to shield Iran's oil and banking industries from U.S. sanctions, Iran will begin enriching uranium to higher levels, ending a commitment made under the deal. The return of U.S. sanctions has been damaging to Iran's economy.

"If the five countries came to the negotiating table and we reached an agreement, and if they could protect our interests in the oil and banking sectors, we will go back to square one," Rouhani said, according to Reuters. The other countries that signed the deal are Russia, China, Britain, France and Germany.

Rouhani said the announced actions are in line with the deal's requirements.

U.S. National Security Advisor John Boltonreleased a statement Sunday night that said the U.S. "is deploying the USS Abraham Lincoln Carrier Strike Group and a bomber task force to the U.S. Central Command region to send a clear and unmistakable message to the Iranian regime that any attack on United States interests or on those of our allies will be met with unrelenting force."

Iran said the aircraft carrier was simply being rotated in as scheduled, and called Bolton's announcement "psychological warfare." The Pentagon confirmed that it was a scheduled rotation but said it had "expedited" the move, Reuters reports.

China's foreign ministry said Wednesday that the U.S. had "further aggravated" tensions with Iran, and called on all parties to exercise constraint, The Associated Press reports. Russian Foreign Minister Sergei Lavrov said the accord had been complicated by Washington's "irresponsible behavior."

NPR International Correspondent Peter Kenyon contributed to this report.

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