Prime Minister Keir Starmer and President Donald Trump held a call about the Iran war, the UK government said, after fierce criticism of the British premier by the US leader.
Trump had lobbed insults at Starmer over the latter's initial refusal to have any role in the US-Israeli war with Iran, which began on February 28.
"The leaders began by discussing the latest situation in the Middle East and the military cooperation between the UK and US through the use of RAF bases in support of the collective self-defence of partners in the region," Starmer's office said in a statement on Sunday.
"The prime minister also shared his heartfelt condolences with President Trump and the American people following the deaths of six US soldiers.
"They looked forward to speaking again soon," the statement added.
It did not mention whether the pair discussed the apparent fracturing of their close relationship over the past week.
Starmer had worked hard to cultivate a warm relationship with the unpredictable Trump, who was given an unprecedented second state visit to Britain last year.
But he angered Trump by refusing to allow British bases to be used for the US's initial strikes on Iran.
He later agreed to a US request to use two British military bases for a "specific and limited defensive purpose".
US bombers began operating at the Fairford site in Gloucestershire, southwestern England, and the UK-US Diego Garcia base on the Chagos Islands in the Indian Ocean on Saturday.
Trump said last week he was "not happy with the UK" and mocked Starmer, saying, "This is not Winston Churchill that we're dealing with.”
In a post late on Saturday, he called Britain "our once great ally” and accused Starmer of trying to "join wars after we've already won!"
Starmer had defended his position by insisting British action "must always have a lawful basis and a viable, thought-through plan".
He has argued that Iran's retaliatory firing of missiles at British allies and interests in the Middle East justified his change of stance.
