"Do not give away Diego Garcia," US President Donald Trump has said as he criticised the UK's plan to hand over the Chagos Islands to Mauritius and lease back an important military base.

Trump said "this land should not be taken away from the U.K." and if it did it would be "a blight on our Great Ally", in a post on social media.

This comes despite Washington on Tuesday giving its official backing to London's plan to cede sovereignty of the British Indian Ocean Territory to Mauritius.

Trump's latest comments come ahead of talks between the US and Mauritius planned for next week.

Diego Garcia is the largest island in the archipelago, and is used by the UK and US armed forces.

Under the plan, the UK will lease back Diego Garcia for a period of 99 years.

Posting on the Truth Social platform on Wednesday, Trump wrote: "I have been telling Prime Minister Keir Starmer, of the United Kingdom, that Leases are no good when it comes to Countries, and that he is making a big mistake by entering a 100 Year Lease..."

The US president stressed that Diego Garcia was "strategically located in the Indian Ocean".

"Prime Minister Starmer is losing control of this important Island by claims of entities never known of before," he said.

"We will always be ready, willing, and able to fight for the U.K., but they have to remain strong in the face of Wokeism, and other problems put before them."

And referring to ongoing US-Iran talks on Tehran's controversial nuclear programme, Trump said: "Should Iran decide not to make a Deal, it may be necessary for the United States to use Diego Garcia... in order to eradicate a potential attack by a highly unstable and dangerous Regime."

The US leader has repeatedly threatened to use military action against Iran over its deadly crackdown on anti-government protests and its nuclear activities.

The US and its European allies suspect that Iran is moving towards the development of a nuclear weapon, something that Tehran has always denied.

The Chagos Islands – officially known as the British Indian Ocean Territory – are located about 5,799 miles (9,332km) south-east of the UK and about 1,250 miles north-east of Mauritius, in the Indian Ocean.

The islands have been under British control since 1814 and were bought by the government for £3m, which led to the establishment of the islands as an overseas territory in 1965.

But Mauritius has long argued that it was illegally forced to give the islands away as part of a deal to gain independence.