WASHINGTON (Reuters) - Draft legislation responding to U.S. President Donald Trump’s refusal to certify the Iran nuclear deal would set tough new terms for the pact, including restoring sanctions if Iran tests a ballistic missile able to carry a warhead or bars nuclear inspectors from any sites.

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Critics of the legislation drafted by Republican Senators Bob Corker and Tom Cotton, with support from the Trump administration, said it could put the United States in violation of the international agreement if it were enacted.

The draft, seen by Reuters on Tuesday, was in the works on Oct. 13 when Trump announced he would not formally certify that Tehran was complying with the international nuclear pact, and called on Congress to write legislation to toughen it.

Since then, Corker has met with Senate Democratic colleagues, at least some of whom would have to back the legislation for it to pass. They have insisted that Washington work with European allies who co-signed the deal before making any changes.

Britain, France, Germany and the European Union, which also signed the nuclear accord - as did Russia and China - warned that Trump’s plan could cause a split with Washington and risked U.S. credibility abroad.

Corker, chairman of the Senate Foreign Relations Committee, told Reuters last week that the Trump administration must work closely with European allies as it develops its new Iran policy.

The draft legislation, a proposed amendment to the Iran Nuclear Agreement Review Act passed in 2015, broadens a required administration assessment on whether Iran is complying with the pact to add factors related to issues from trade to whether Iran is using commercial aircraft licensed by the United States for non-civil aviation purposes.

As previously reported, it would instantly reimpose, or “snap back” sanctions lifted under the agreement if Iran were deemed capable of developing a nuclear weapon within a year.

The Iran issue has been complicated by Trump’s recent attacks on Corker, in which he blamed him for the nuclear deal forged under former Democratic President Barack Obama. The pact, which world leaders have urged Trump not to derail, was opposed by every Republican in Congress including Corker.

Corker has lashed back at Trump by saying he has failed to grow into the job as president and blaming him for breaking down important international relationships.

A spokeswoman for Corker did not immediately respond to a request for comment on how the dispute with the president might affect the Iran legislation.