In April 2019 the U.S. threatened to sanction countries continuing to buy oil from Iran after an initial six-month waiver announced in November 2018 expired. According to the BBC, U.S. sanctions against Iran "have led to a sharp downturn in Iran's economy, pushing the value of its currency to record lows, quadrupling its annual inflation rate, driving away foreign investors, and triggering protests." In December 2018, Iran's President Hassan Rouhani warned: "If one day they want to prevent the export of Iran's oil, then no oil will be exported from the Persian Gulf."