Iran threatened Wednesday to restart enriching uranium in 60 days if world powers fail to negotiate new terms for the 2015 nuclear agreement. In a televised speech, President Hassan Rouhani also said that Iran would stop exporting extra uranium and heavy water from its nuclear program. The export of heavy water and extra uranium were requirements of the deal. Enriched uranium can be used to make nuclear weapons. Heavy water is used to cool nuclear reactors. Rouhani did not explain how much uranium it would enrich. One year ago, U.S. President Donald Trump withdrew from the agreement. China, Russia and European nations are still part of the deal, however. After the United States withdrew from the deal, it put strong sanctions on Iran. The move caused a severe economic crisis.