Brian Hook's departure comes as Washington fights a losing battle to get UN Security Council members behind new weapons limitations; he'll be replaced by Elliott Abrams

US secretary of state indicates Washington may seek new UN sanctions on Tehran, as signatories Russia and China continue to support embargo's scheduled end in October

'Great Prophet 14' maneuvers, held as US pushes to renew UN weapons sanctions on Tehran, include fast attack boat and drone attacks on a mock American carrier

Russia and China, looking to Tehran for arms contracts, oppose extension of UN Security Council moratorium on Iran that expires in October

Tehran's FM says Washington 'must be stopped before disaster' occurs after fighter jet approaches civilian flight; Iran aviation agency calls for probe by international body

Media reports claim warplane or planes forced Mahan Air flight to Beirut to make sudden altitude change, injuring passengers; some reports indicate jets from US

Satellite images show Dominica-flagged MT Gulf Sky in Iranian waters; captain confirms seizure to rights group

Under 25 year agreement reportedly finalized, Beijing and Tehran to increase military cooperation, including weapons development and intel sharing; China getting discount oil

Rouhani says 'the people will not accept' long-term closures after health minister blames US sanctions for 'empty coffers'; death toll hits 12,635

Brian Hook, US pointman on Iran, says Trump willing to use force to prevent Tehran acquiring nukes; downplays fears annexation could harm Israel's ties with Arab states