Irans oil minister said on Twitter on Monday that Tehran's oil industry will not yield to pressure from the United States.
Minister Bijan Zanganeh said U.S. sanctions against him and his colleagues "are a passive reaction to Washingtons failure to cut Tehrans oil exports to zero."
"The era of unilateralism is over in the world. Iran's oil industry will not be hamstrung," Zanganeh added.
The United States on Monday imposed fresh Iran-related sanctions targeting the Islamic Republic's oil sector, including the Iranian Ministry of Petroleum.