The United States on Tuesday defended its re-imposition of sanctions against Iran as a legal and justified national security measure that cannot be challenged by Tehran at the United Nations’ highest court, AP reported.

U.S. State Department legal advisor Jennifer Newstead urged judges at the International Court of Justice to reject an urgent request by Iran to order the suspension of sanctions re-imposed by President Donald Trump in May.

Iran filed a case with the court in July challenging the re-imposition. Tehran alleges that the move breaches a 1955 bilateral agreement known as the Treaty of Amity that regulates and promotes economic and consular ties between the two countries, which have been sworn enemies for decades.