In rare move against another country's top diplomat, Washington freezes Mohammad Javad Zarif's assets, appearing to close door on negotiations

FM Zarif claims increased tensions are 'due to America's economic terrorism and Europe's inability to fulfill its commitments'

FM Zarif says if US secretary of state is really open to talking, he should grant visas to Iranian journalists so they can interview him on his home turf

Washington Post quotes official saying Trump administration remains committed to eventually ending waivers allowing work on Iranian civil nuclear program

Cancer patients and victims of other debilitating diseases struggling as drug prices soar; Pompeo says restrictions proving 'incredibly effective' in curbing malign activities

London dispatches warship to Gulf to escort UK-flagged tankers across world's busiest oil shipping lane amid escalating tensions

At Vienna summit, deputy FM tells remaining signatories of ailing 2015 pact they 'must not create any obstacles' to Tehran's oil exports

Diplomats examining the accord after Iranians flout the uranium stockpile and enrichment limits set out in the 2015 agreement

Tehran's atomic agency chief briefs lawmakers on unraveling nuclear deal, as remaining signatories after US pullout set to meet in Vienna

Tehran pessimistic about deal's prospects, while Europeans plan to raise subject of Iran's 'proven violations of their commitments' amid rising Gulf tensions