Iran deal, formally known as the Joint Comprehensive Plan of Action (JCPOA) - All You Need To Know

Iran deal, formally known as the Joint Comprehensive Plan of Action (JCPOA) is an agreement between Iran and the five permanent members of the UN Security Council plus  Germany and the EU to ensure its nuclear programme is limited to civilian use

The deal, which was signed in October 2015 and implemented at the start of 2016, followed years of negotiation between the US, represented by then-Secretary of State John Kerry, and Iran, represented by Foreign Minister Mohammad Javad Zarif

The agreement requires Iran to completely eliminate stockpiles of medium-enriched uranium and drastically reduce reserves of low-enriched uranium. 

The material in its high-enriched form is required to produce nuclear weapons. Iran denies that it has ever had the aim of producing a nuclear weapon. 

Iran also agreed to reduce the number of centrifuges capable of enriching uranium.

In return, UN sanctions related to Iran's nuclear programme were lifted, as were some EU sanctions.

The US ended some secondary sanctions against non-US businesses and individuals who engaged in commercial activity with Iran. 

Frozen Iranian assets, valued at over $100bn, were also released back to Tehran

Who ensures Iran abides by its side of the deal?

The International Atomic Energy Agency (IAEA) has repeatedly confirmed Iran's compliance with the deal.

Why does Trump need to certify Iran's compliance with JCPOA?

The Obama administration faced heavy criticism from Republicans, as well as from some members of his own Democratic Party for signing up to the deal, which they saw as excessively compromising.

Opponents of the then-US president passed legislation requiring US presidents to certify Iran's compliance with the deal every 90 days. 

The Trump administration declared that Iran is complying with the nuclear deal in May and July, but threatened more sanctions for breaching the "spirit' of the agreement. 

The deadline for certification is October 15, but it is believed that Trump will announce his decision sooner. 

White House spokeswoman Sarah Sanders said this week that the president "has reached a decision on an overall Iran strategy". 

Trump has repeatedly called the agreement the "worst deal ever" and had promised to tear it up even before he was elected. 

What will happen if Trump refuses to certify the Iran nuclear deal? 

If Trump refuses to certify, the issue goes to Congress. 

Lawmakers will have a non-binding 60 day period to debate the deal.

Congress can decide to introduce or restore sanctions.

It remains to be seen whether that will actually happen as several prominent Republicans are undecided on the issue or do not want the deal to unravel.

Would Trump be violating the nuclear deal?

Not certifying the deal would not be a violation of JCPOA in itself, however, it does pave the way for Congress to introduce new sanctions, which could be in breach of US commitments under the agreement.

The onus on breaching the deal would, therefore, be with US lawmakers