Tehran's foreign minister Zarif reacts with fury to Trump warning of 'heavy price' if US troops targeted again

Medical goods sent to Tehran using INSTEX, a complicated barter method aimed at enabling commerce with the Islamic Republic without falling afoul of US sanctions

Vienna meeting comes as European parties try to persuade Tehran to come back in line with the deal after taking steps away in protest at US pulling out and reimposing sanctions

UK reportedly says not enough notice given for PM's visit on NATO sidelines; Merkel, Macron said not eager to meet him amid criticism on Iran moves

Terse statement from White House says leaders also talk about 'other critical bilateral and regional issues,' but gives no details

As 6 nations join INSTEX barter system, PM calls move a betrayal of Middle Easterners 'standing up to Iran and its henchmen'; says Europeans 'should be ashamed of themselves'

France, Germany and UK welcome Belgium, Netherlands and others to INSTEX, mean to allow Iran to continue selling oil despite US restrictions

Experts say measure looks like aimed at gathering intelligence and could increase burden for humanitarian trade, amid accounts of Iranians going without vital medicine

Germany confirms INSTEX won't be headed by ex-diplomat Bernd Erbel, who gave pair of interviews to journalist who claimed 'Holocaust industry' inflates number of victims

Iranian official says talks in Vienna with remaining signatories to 2015 accord 'could not satisfy Iran’s just demands'