21 Dec 2018 - (AP) A US aircraft carrier sailed into the Persian Gulf on Friday, becoming the first since America's withdrawal from the Iran nuclear deal and breaking the longest carrier absence in the volatile region since at least the September 11 terror attacks. The arrival of the USS John C. Stennis came as Iranian officials returned to repeatedly threatening to close off the Strait of Hormuz, the narrow mouth of the Persian Gulf through which a third of all oil traded by sea passes. Throughout its trip on Friday, some 30 Iranian Revolutionary Guard vessels trailed the Stennis and its strike group. Despite being so narrow and within the territorial waters of Iran and Oman, the strait is viewed as an international transit route. American forces routinely travel through the area, despite sometimes-tense encounters with Iran's Revolutionary Guard, a paramilitary force answerable only to Supreme Leader Ayatollah Ali Khamenei. Tensions have been high since US President Donald Trump's May withdrawal from Iran's nuclear deal, which saw sanctions lifted for Tehran limiting its uranium enrichment. Iranian President Hassan Rouhani, a relative moderate within the country's Shiite theocracy whose major achievement was the deal, has repeatedly warned any attempt to stop Iran's export of crude oil could see it close off the strait.