US President Donald Trump has said the country's navy will protect ships in the Middle East "if necessary" in a bid to stop the energy supply crunch sparked by the war with Iran.

Trump added that the government will provide "at a very reasonable price, political risk insurance and guarantees for ALL Maritime Trade, especially Energy, traveling through the Gulf".

He said his plan "will ensure the FREE FLOW of ENERGY to the WORLD".

Trump made the announcement on social media as global oil and gas prices continued to surge, sparking global concerns about the impact on household prices.

Oil has jumped 10% since the US and Israel launched their campaign over the weekend, reaching the highest level since last June.