US President Donald Trump said on Thursday that Iran should not charge fees to tankers going through the Strait of Hormuz, which has been blockaded since the start of the Iran war.

"There are reports that Iran is charging fees to tankers going through the Hormuz Strait," Trump wrote in a post on his Truth Social platform.

"They better not be and, if they are, they better stop now," he added.

Media reports have suggested Iran might want to charge a toll for ships passing through. Western leaders have pushed back on the idea of paying any such fees.

On Wednesday, an Iranian official was quoted by the Financial Times as saying that Iran would demand toll payments in cryptocurrency to retain control over Hormuz during a two-week ceasefire with the US.

In a separate post on Thursday, without elaborating, Trump said "you'll see Oil start flowing, with or without the help of Iran."

Trump announced a ceasefire with Iran on Tuesday, after having previously threatened to destroy Iran's entire civilization.

Ship traffic through the strait stood at well below 10% of normal volumes on Thursday despite the fragile ceasefire as Tehran asserted its control by warning ships to keep to its territorial waters while doing so, according to the Reuters news agency.