British Prime Minister Keir Starmer insisted on Friday that NATO was "in America's interests", at the end of a three-day visit to the Gulf to discuss bolstering the "fragile" Middle East truce.

Starmer's comments followed United States President Donald Trump's renewed attacks this week on the Western military alliance and his threats to withdraw from it, after a refusal by NATO allies to join the US-Israel war against Iran.

"It is in America's interests. It's in European interests," Starmer told UK broadcasters of the nearly 80-year-old security bloc.

"NATO is a defensive alliance, which for decades has kept us much safer than we would otherwise have been," he added, while reiterating European members "need to do more" financial burden sharing.

Starmer spoke before leaving Qatar, the last stop of his tour of the war-hit region, which also included visits to Saudi Arabia, the United Arab Emirates and Bahrain

The British leader talked by phone to Trump late on Thursday, when he said he set out "the views of the region here" to the US president, primarily centred on the Strait of Hormuz.

The crucial maritime chokepoint has remained largely closed in recent days. It was due to be re-opened under a temporary ceasefire between the US and Iran, announced this week, but has been jeopardized by Israeli attacks on Lebanon and accusations that the truce is not being implemented.

"We spent most of the time on the call talking about the practical plan that's going to be needed to get navigation through the strait and the role that the UK is playing," Starmer said.

He said Britain was building a coalition of over 30 countries to work on a diplomatic and military plan to get vessels moving through the waterway.

In an earlier interview, Starmer had appeared to draw parallels between Trump and Russian President Vladimir Putin, expressing frustration over rising oil and other costs linked to the war.

"I'm fed up with the fact that families across the country see their bills go up and down on energy, businesses' bills go up and down on energy, because of the actions of Putin or Trump," he said.

Starmer later spoke by phone to the Prime Minister of Pakistan, Shehbaz Sharif, ahead of planned ceasefire talks in the South Asian country.

Starmer thanked Sharif for his "critical role" in securing the temporary, two-week truce, according to a readout issued by Starmer's Downing Street office.