According to the London-based daily, Washington is demanding clarity regarding UK Prime Minister Boris Johnson's position on anti-Iranian sanctions.
"The central question is whether or not Britain supports allowing the world’s largest state sponsor of terrorism to buy and sell weapons. Our administration has repeatedly stated that the United States will never allow this to happen," US Envoy to the United Nations Kelly Craft told the Times.
The UK government spokesman, in turn, said that London "shared the US concern about Iranian proliferation and the impact this has on regional security," as cited by the media outlet.
US President Donald Trump told reporters on Wednesday that he had asked Secretary of State Mike Pompeo to notify the United Nations Security Council that the United States intends to restore all snapback sanctions on Iran.
The State Department said in a statement later in the day that Pompeo would be at the United Nations on Thursday and Friday.
Iran was designated as a state sponsor of terrorism in 1984.
The United States has announced plans to trigger the snapback mechanism to reimpose all United Nations sanctions against Iran — previously lifted under the 2015 nuclear agreement — after failing to get the UN Security Council to pass a resolution aiming to indefinitely extend the arms UN embargo on Iran.
The arms embargo is set to expire in October under the terms of the nuclear agreement.
Under the terms of the nuclear agreement, all previous sanctions on Iran would be reinstated if the United States vetoes the resolution. However, the United States unilaterally withdrew from the nuclear agreement on May 8, 2018.