Earlier this month, the European Union put forth a proposal to revive the 2015 Iran nuclear deal.

Reuters reports that on Monday, Josep Borrell, the E.U.’s foreign policy chief, said he hoped the United States would respond to the proposal this week.

Under the 2015 plan, formally known as the Joint Comprehensive Plan of Action (JCPOA), Iran agreed to significantly cut back its controversial uranium enrichment program. The E.U., U.S., and other signatories were concerned that the program could be a possible pathway for Iran to build to nuclear weapons. In return, Iran was granted relief from international sanctions. Iran has denied any ambitions to build nuclear weapons and says it wants nuclear power only for peaceful purposes.

In May 2018, then-President Donald Trump abandoned the JCPOA, calling it "defective at its core." Trump reinstated all U.S. sanctions on Iran as part of campaign to compel Iran to negotiate a replacement agreement that would further restrict its military efforts, according to the BBC.

Borrell said that Iran had given a "reasonable" response to the new proposal. "There was a proposal from me as coordinator of the negotiations saying, 'This is the equilibrium we reached, I don't think we can improve it on one side or the other'... and there was a response from Iran that I considered reasonable," Borrell said at an event in Spain.

The proposal “was transmitted to the United States which has not yet responded formally... I hope the response will put an end to the negotiations," Borrell stated.

Al Jazeera reports that Iran’s stockpile of enriched uranium is now at 60 percent enrichment, its highest ever and significantly higher than the 3.67 percent limit set out in JCPOA. Ninety percent enrichment is needed to build a nuclear bomb.

Last week, Iran’s negotiating team adviser Mohammad Marandi said, “We’re closer than we’ve been before” to securing a deal and the “remaining issues are not very difficult to resolve.”

On August 10, the United States charged a member of Iran’s Islamic Revolutionary Guard Corps with plotting to murder John Bolton, a national security adviser to Trump. According to Reuters, U.S. official do not believe the charges should affect the nuclear talks with Tehran.

The E.U. proposal has not yet been made public.