Russia is “extremely concerned” by U.S. President Donald Trump’s comments questioning the Iran nuclear deal and suspects that Washington itself may have violated a landmark arms control treaty, Foreign Minister Sergei Lavrov leading Russian delegation at UN General Assembly said.

Lavrov’s comments, made to international reporters at the United Nations in New York and published by his ministry on Wednesday.

Lavrov, whose country is a signatory to the deal, said Russia strongly disagreed with that stance. “It’s extremely worrying,” he underlined. “We will defend this document, this consensus, which was met with relief by the entire international community and genuinely strengthened both regional and international security.”