The United States on Friday issued fresh Iran-related sanctions as the war hit its six-month mark in a move that was rebuffed by Tehran as “state terrorism.”

Iran condemned the United States’ new economic sanctions and said other countries were legally obliged not to implement them. The Iranian foreign ministry’s statement came as mediators stepped up efforts to reopen the Strait of Hormuz, which handled 20% of world oil supplies before the war began and whose status remains the biggest obstacle to a peace deal.

US President Donald Trump’s administration on Monday warned countries to cut their business ties with Iran or face secondary sanctions as part of what it billed as an “economic D-Day,” though the Treasury Department stopped short of actually imposing penalties.

Trump reiterated on Thursday that the US was not talking with Iran, while the White House said Washington’s economic campaign would continue until Tehran decided to “come to the table in a meaningful way.”

Iran’s foreign ministry said in a statement on Friday that all countries were obligated under international law to refrain from implementing US sanctions against Tehran, adding that participation in them amounted to complicity in imposing one state’s unlawful will on independent states.