Iran will pull out of a landmark deal to stop the country from developing nuclear weapons unless it receives concrete guarantees that the economic incentives of the pact will be protected by the other parties, following the U.S. decision to unilaterally withdraw and Washington's threat of sanctions against companies that trade with Iran, a senior Iranian official said Friday.

Iran wants European powers to present it with measures by the end of May to compensate it for the U.S. decision to abandon the 2015 nuclear deal, a senior official said on Friday, and Tehran would decide within weeks whether to quit the accord.

The 2015 agreement between Iran and world powers lifted international sanctions on Tehran. In return, Iran agreed to curbs on its nuclear program.

Since President Donald Trump pulled the U.S. out last month, European states have been trying to find a way to ensure Iran still gets the economic benefits to persuade it to stay in the deal. But that has proven difficult, with European companies frightened away by U.S. sanctions.

Nations that remain in the agreement – Britain, China, France, Germany and Russia – began meetings on Friday for the first time since Trump left the pact, but diplomats see limited chance to salvage it. Their officials with Iran's deputy foreign minister will try to flesh out a strategy to save the deal by keeping oil and investment flowing.

EU leaders have united behind the accord, with Brussels working on measures, including banning EU-based companies from complying with re-imposed U.S. sanctions and urging governments to make money transfers to Iran's central bank to avoid fines.

Iran's supreme leader set out conditions on Wednesday for Iran to stay in the deal: Unless Europe guarantees Iran's oil sales will not be hurt, Tehran would resume enrichment of nuclear material. He also rejected any new negotiations over Iran's missile program, which was not covered in the nuclear deal. The official said time was running out and that if Iran was not satisfied by European efforts, Iran would seek a ministerial meeting before making its decision.

Iran has struggled to benefit from the accord so far, partly because of remaining unilateral U.S. sanctions that have deterred major Western investors from doing business with Tehran. Some Western companies have already quit Iran or said they may have to leave because of the new U.S. sanctions.

U.S. Secretary of State Mike Pompeo last week called for the negotiation of a new deal that would go far beyond the single focus of the 2015 agreement and would have the status of a formal treaty; a suggestion Iran flatly rejects.

"There is no trust at all to engage with the U.S. on any subject," the official said. "We made the JCPOA in good faith and we remained committed to the JCPOA and they just pulled out ... so name me a single reason why we should enter into a new negotiation with the U.S. or a new deal? One president signs, the other president nullifies; I don't think anybody can negotiate with the U.S. with such behavior."

The official noted that the International Atomic Energy Agency on Thursday reported Iran had complied with limits on the level to which it can enrich uranium, its stock of enriched uranium and other items. IAEA Director General Yukiya Amano was invited by the Joint Comprehensive Plan of Action (JCPOA) on Friday to address the group on his agency's findings. If it pulls out of the deal, Iran would likely revert to its nuclear doctrine before the agreement or maybe even escalate its activities, the official said.