President Donald Trump is set to announce Tuesday his decision on whether to keep the United States in the nuclear agreement struck between Iran and a group of world powers three years ago.
The president had given himself until Saturday to make a choice about continuing to waive U.S. sanctions targeting Iran's oil sector and central bank. Those measures, along with others imposed by the European Union and other individual nations, were originally put in place to pressure Iran to give up its alleged pursuit of nuclear weapons.
Iran insisted its nuclear program was solely peaceful, and as part of the deal with the U.S., Britain, China, France, Russia and Germany it agreed to limit its nuclear activity to allay fears in exchange for relief from those sanctions that badly hurt its economy.
Trump tweeted that his announcement would come at 1800 GMT Tuesday.
He has long been critical of the agreement, and said Monday it was "very badly negotiated." Among his chief objections are a lack of provisions addressing Iran's ballistic missile activity and the fact that the Iran's responsibilities, such as limiting its uranium enrichment, expire after a set number of years.
Iran has long maintained it has every right to have a missile program for defense. Ahead of Trump's announcement, Iranian President Hassan Rouhani said Iran would be willing to remain a party to the nuclear deal if the other signatories maintain their part of the agreement.
WATCH: Trump's upcoming decision
The text of the document, formally known as the Joint Comprehensive Plan of Action, states in multiple places that Iran would treat the reinstatement of sanctions "as grounds to cease performing its commitments" in whole or in part.
In recent weeks European allies have been lobbying Trump to keep the existing deal in place while signaling a willingness to address ballistic missiles and Iran's actions in the Middle East through supplemental negotiations.
"We think we'll be tougher on Iran but not throw away that the heart of the deal, which is all about stopping them getting a nuclear weapon," British Foreign Secretary Boris Johnson said Monday in Washington, where he met with Vice President Mike Pence and Secretary of State Mike Pompeo.
Johnson said it is clear Iran will not want to renegotiate the JCPOA.
"The core of it they will want to keep. But what we can do is be tougher on them in other respects and try to address that key question: what happens when the deal expires? And that's where, actually, to be fair, I think the president of the United States has a valid point and we need we need to address that with our European friends and with other partners," he said.
French President Emmanuel Macron said during his own visit last month that while no agreement is perfect, there is no alternative strategy for the Iran nuclear deal.
Democratic Senator Bob Menendez told reporters Monday he would advise Trump to remain part of the agreement "unless he has a clear pathway forward that doesn’t split us from our allies and leave Iran laughing all the way."