Republican Senators Bob Corker and Tom Cotton are reportedly working on new draft legislation that would set tough terms for the multilateral Iran deal in response to President Donald Trump’s refusal to certify Tehran’s compliance with the 2015 nuclear accord.

The draft, seen by Reuters on Tuesday, sets tough new terms for the nuclear deal, formally known as Joint Comprehensive Plan of Action (JCPOA), including restoration of sanctions if Iran tests a ballistic missile capable of carrying a warhead or prevents nuclear inspectors from visiting any sites.

The motion, according to the report, was already under preparation when Trump delivered his anti-Iran speech on October 13, in which he said he would not be certifying Iran’s compliance with the terms of the JCPOA under a domestic American law, kicking to Congress a decision on whether to restore sanctions against Iran.

Trump did not pull Washington out of the JCPOA, but he gave the US Congress 60 days to decide whether to re-impose the economic sanctions against Tehran that were lifted under the pact.

The draft legislation is a proposed amendment to the Iran Nuclear Agreement Review Act passed in 2015. It extends the US administration’s assessment of Iran’s compliance with the nuclear deal, but adds other issues to be examined, such as trade with Iran or ensuring that Tehran is using US-licensed aircraft for civilian purposes.

It also stipulates that the US would immediately re-impose or “snap back” sanctions against Iran if the country were deemed capable of developing a nuclear weapon within a year.

Re-imposing sanctions would put the US at odds with other signatories to the accord and the European Union.

Critics warn that if the legislation, drafted by Republican senators Bob Corker and Tom Cotton with support from the Trump administration, is enacted, it could put the US in breach of the international pact.

Corker has met with Democratic Senators, as the legislation requires the approval of at least some of them. The Democratic Senators have reportedly insisted that the US should work with its European allies, who co-signed the agreement before making any decision.

Republican Senator Bob Corker speaks to the media at the Capitol Hill on October 24, 2017. (Photo by AFP)

Trump and Corker have already been engaged in a war of words over a variety of issues, including the Iran nuclear deal. While Trump blames the Republican Senator for the approval of the JCPOA by the US, the latter criticizes the president for breaking down important international relationships.

A spokeswoman for Corker did not immediately comment on how the dispute with Trump might affect the Iran legislation.

The European Union and the signatories to the nuclear deal -- Britain, France, Germany, Russia and China -- have warned that Trump’s plan could cause a split with Washington and jeopardize the US credibility when it comes to deal making.

After the leaders of the UK, France and Germany failed to convince Trump of the dangers of killing the JCPOA, they have now focused their lobbying efforts on the US Congress.

EU Ambassador to the US David O’Sullivan and his French, German, and British counterparts met with congressional lawmakers earlier this month to explain why Europe believes Iran’s nuclear deal is working.

On October 16, the union’s foreign ministers held a closed-door meeting, chaired by EU foreign policy chief, Federica Mogherini, on the best way to proceed with the Iran issue.

The EU foreign policy chief, Federica Mogherini, speaks to journalists in Brussels on October 19, 2017. (Photo by AFP)

The top European diplomats urged US lawmakers not to re-impose sanctions on Tehran and warned against the serious consequences of harming the international agreement backed by the UN Security Council.

Meanwhile, besides senior officials in Moscow who have staunchly defended the JCPOA, lawmakers in the upper house of Russia’s parliament are set to call on their colleagues in the US Congress and other Western legislatures to do all in their power to help protect the deal.

The Russian Federation Council’s Foreign Affairs Committee has prepared a draft statement, planned to be put to vote on Wednesday, to warn against Trump’s threats against the Iran deal.