Donald Trump and British foreign secretary David Cameron had dinner on Monday at the Republican presidential candidate's Florida home where they discussed the Ukraine war and "the need for Nato countries to meet their defence spending requirements".
Mr Trump's campaign revealed details of the meeting.
The meeting kicked off a visit by Mr Cameron to the US during which he met secretary of state Antony Blinken in Washington on Tuesday and afterward will press lawmakers in Congress to pass an aid package for Ukraine.
Over dinner at Mr Trump's Mar-a-Lago estate, the two men discussed "the upcoming US and UK elections, policy matters specific to Brexit, the need for Nato countries to meet their defence spending requirements, and ending the killing in Ukraine," Mr Trump's campaign said in a statement.
Speaking at a press conference alongside Mr Blinken in Washington, Mr Cameron said the dinner was in line with past precedent of government ministers meeting with opposition politicians but declined to say what specifically they discussed.
"(We) discussed a range of important geopolitical subjects," Mr Cameron said.
Mr Trump has frequently taken aim at the failure of many of Nato's 32 members to meet a defence spending target of at least 2 per cent of gross domestic product. This has raised concern in Europe about the trans-Atlantic military alliance's future if Mr Trump beats incumbent US president Joe Biden, a Democrat, in a November election.
In February, Mr Trump sparked fierce criticism from Western officials for suggesting he would not protect countries that fail to meet the alliance's defence spending targets, and would even encourage Russia to attack them. The US military forms the core of the alliance's military power.
European leaders have been reaching out to US lawmakers, business leaders and think tanks as part of efforts to influence the Trump camp about defence spending, Europe's role in US-China relations, and aid to Ukraine.
A British Foreign Office spokesperson said on Monday that Mr Cameron was meeting with Mr Trump as part of "routine international engagement," describing it as "standard practise for ministers to meet with opposition candidates".
A British embassy spokesperson said Mr Cameron would not be meeting Republican House of Representatives speaker Mike Johnson due to scheduling issues. Last week, Mr Cameron said he would urge Mr Johnson to pass a $60 billion (€55 billion) package of military aid for Ukraine, which has been held up for months.
