(Bloomberg) -- The U.K. should support U.S. President Donald Trump’s plan to impose strict sanctions on Iran rather than stand by the 2015 deal to curb the country’s nuclear program, the American envoy to London said in an opinion piece.

Writing in the Sunday Telegraph newspaper, Ambassador Woody Johnson said Iran’s "malign and reckless activities" must be put to an end through sanctions. He accused the Iranian government of spending billions of dollars to destabilize the Middle East, fighting "proxy wars" in Syria and Yemen.

Tensions between Washington and Tehran have escalated dramatically since Trump withdrew from an international deal governing Iran’s nuclear program in May and imposed stringent sanctions on its economy. The next round of penalties, affecting Iran’s oil industry, are due to come into effect on Nov. 5.

The accord between Iran and six world powers including the U.S. and U.K. traded sanctions relief for the curbing of Tehran’s nuclear program.

"America is turning up the pressure and we want the U.K. by our side. It is time to move on from the flawed 2015 deal," Johnson wrote. “We are asking global Britain to use its considerable diplomatic power and influence and join us as we lead a concerted global effort towards a genuinely comprehensive agreement."

To contact the reporter on this story: Jeremy Hodges in London at jhodges17@bloomberg.net

To contact the editors responsible for this story: Reed Landberg at landberg@bloomberg.net, Amy Teibel, Keith Campbell

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