The International Energy Agency agreed on Wednesday to release 400 million barrels of oil to cushion a supply disruption triggered by the war in Iran.
But the move did little to calm energy markets, as shipments through the Strait of Hormuz remain effectively frozen.
Oil prices ticked up Wednesday on worries of a sustained interruption to global flows.
US President Donald Trump suggested oil companies could use the strait, but strikes on ships have escalated and the US military declined to escort tankers until the threat of Iranian attacks subsides.
Even as Tehran has jeopardized global oil supplies, it has shipped nearly 12 million barrels of its own crude to China since the war began.
