WASHINGTON — U.S.-Iran relations took a tense new turn Wednesday as U.S. Secretary of State Mike Pompeo threatened Tehran over attacks on U.S. missions in Iraq and announced the termination of a 60-year old amity treaty with Tehran.

At a State Department press conference Wednesday, Pompeo announced the U.S. is unilaterally exiting the 1955 Treaty of Amity with Iran, which covers economic relations and consular rights, calling the move decades overdue and Iran’s claims under the treaty “meritless.”

The U.S. and Iran have seen their relationship deteriorate since President Donald Trump in May pulled the United States out of the Obama-era nuclear deal, which lifted sanctions in exchange for limits on Tehran’s nuclear program.

The Trump administration’s new move follows the United Nations International Court of Justice’s reprimand of the United States on Wednesday. The court issued a provisional ruling that Washington’s reimposition of sanctions on Iran are a violation of the treaty and ordered the U.S. to lift restrictions linked to humanitarian trade, food, medicine and civil aviation.

Pompeo, at the press conference, pointed to the court’s finding that Iran hadn’t complied with the treaty’s nonproliferation language and said the U.S. had been addressing the humanitarian concerns raised by the court independent of the ruling. He said the administration was “disappointed” by the ruling.

“Iran is attempting to interfere with the sovereign rights of the United States to take a lawful action necessary to protect our national security — and Iran is abusing the ICJ for political and propaganda purposes,” Pompeo said.

Tehran was the source of a Sept. 29 rocket attack to the U.S. diplomatic missions in Baghdad and Basra which led to Basra consulate’s closure, Pompeo said Wednesday. He had previously blamed the Islamic Revolutionary Guard Quds Force and militias under the control of Qassem Suleimani, the commander of the Quds Force.

“We can see the hand of the ayatollah and his henchmen in these attacks on the United States,” Pompeo said, adding that he had, “warned the Iranian government that we will hold it directly responsible for any harm to Americans or our diplomatic facilities whether perpetrated by Iranian forces or by associated proxies of elements of those militias."