Boris Johnson has told Joe Biden that gains made in Afghanistan must not be lost, as the leaders spoke on the phone about a coordinated response.
The call follows a wave of criticism from US media and British and European politicians following the Taliban's takeover.
Mr Johnson and the US President agreed to hold a virtual G7 leaders’ meeting next week to discuss a common strategy and approach to Afghanistan.
The two leaders "discussed the need for continued close coordination among allies and democratic partners on Afghanistan policy going forward,” the White House said.
This will include ways further humanitarian assistance and support for refugees and other vulnerable Afghans can be provided, it added.
UK Prime Minister Mr Johnson stressed to US President Joe Biden the importance of preserving the gains made in Afghanistan, Downing Street has said.
A No 10 spokesperson confirmed Mr Johnson had spoken to Mr Biden on Tuesday.
They said in a statement: "The leaders welcomed US and UK cooperation in recent days to help evacuate our nationals, current and former staff, and others from Afghanistan.
“They resolved to continue working closely together on this in the days and weeks ahead to allow as many people as possible to leave the country.
"The Prime Minister and President Biden agreed on the need for the global community to come together to prevent a humanitarian crisis in Afghanistan.
“The Prime Minister outlined UK plans including increased humanitarian aid to the region and resettlement of refugees.
"The Prime Minister stressed the importance of not losing the gains made in Afghanistan over the last 20 years, of protecting ourselves against any emerging threat from terrorism and of continuing to support the people of Afghanistan.
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"The Prime Minister and President looked forward to discussing this issue further at a virtual meeting of G7 leaders in the coming days."
The decision by Mr Biden to stick to the troop withdrawal deal struck by his Republican predecessor Donald Trump has stirred widespread criticism at home and among US allies.
The US and Western allies resumed evacuating diplomats and civilians on Tuesday, the day after scenes of chaos at Kabul airport as Afghans thronged the runway.
As they rush to evacuate, foreign powers are assessing how to respond to the transformed situation on the ground after Afghan forces melted away in just days, with what many had predicted as the likely fast unraveling of women's rights.
