US President Donald Trump warned of economic consequences against any country that provided "any type of lifeline to Iran" as the US looks to resolve a war it began alongside Israel nearly six months ago.Thousands of people have been killed in the war, which quickly drew in countries across the Gulf, and global markets have been shocked as Iran flexed its ability to control shipping through the Strait of Hormuz, through which about a fifth of the world's traded oil passed before February.

The U.S. and Iran have twice announced ceasefire agreements, in April and June, designed to restore the free flow of shipping through Hormuz to pre-war levels on the way towards ending the conflict, but both quickly crumbled even as Israel has largely withdrawn from the fighting.

In a message posted on social media on Wednesday evening, Trump promised "Economic Warfare and Isolation on an unprecedented scale," although details were scant. Iran has weathered continuous punishing economic sanctions for nearly 50 years, since the Islamic Revolution of 1979.

"Any country that allows its financial institutions, businesses, airports, or government entities to provide any type of lifeline to Iran will itself face tremendous economic consequences," Trump wrote.