US President Donald Trump accused Iran of stepping up its "aggression" after signing a nuclear accord in 2015, saying Tehran took advantage of a lifting of sanctions to fund a missile programme.
"In the years since the deal was signed, Iran's aggression only increased," Trump said in a speech at the United Nations Security Council.
"The regime used new funds from the deal to support terrorism, build nuclear capable missiles and foment chaos." Trump pulled the United States out of the internationally brokered accord in May although European allies and Iran have pledged their continued commitment to the agreement which lifted sanctions in return for curbs in Tehran's nuclear programme.
The United States has been steadily reimposing sanctions against Iran in recent months and Trump said more were on the way.
"Following America's withdrawal (from the accord), the United States began reimposing nuclear-related sanctions on Iran. All US nuclear-related sanctions will be in full force by early November.