"Every country or person who buys ANY AMOUNT of oil or PETROCHEMICALS from Iran will immediately be subject to secondary sanctions", he writes on his platform Truth Social.
Since Trump took office as president, he has stepped up his "maximum pressure" policy towards Iran, with the aim of reducing Iranian oil exports to zero.
The American crude oil rises 1.7 percent in price to 59.1 dollars per barrel. The North Sea oil, Brent, also rises with 1.7 percent and is traded for 62 dollars per barrel.
Trump has also initiated negotiations with Iran about the Iranian nuclear energy program. The UN's atomic energy agency IAEA has warned that Iran is approaching its own nuclear weapon, which Iran denies.
