Dominic Raab has hit back at Pentagon claims that the US kept open a Kabul airport gate to help with the British evacuation effort despite a high risk of attack.
Some government insiders and Tory MPs are said to have accused the US of trying to 'shift the blame' following the horrifying terror attack last week.
Two suicide bombs were detonated outside Kabul's airport on Thursday, killing 13 US troops and as many as 169 Afghans.
US President Joe Biden vowed that the US would hunt down those responsible for the attack, saying he had ordered the Pentagon to come up with plans to strike at the perpetrators.
The nation went on to launch a deadly drone strike against Islamic State-Khorasan (ISK), who claimed responsibility for the slaughter.
Leaked messages, obtained by Politico, claim that before the massacre senior military chiefs had warned of an imminent 'mass casualty event.'
Kabul commanders said that Abbey Gate, where American citizens had been told to gather to gain entrance to the airport, was the “highest risk” from an ISK attack.
It was said that US forces chose to keep the gate open longer than they wanted to allow Brit allies to continue evacuating their personnel.
But the Foreign Secretary said the claims were "just not true".
Mr Raab told Sky News: "We co-ordinated very closely with the US, in particular around the Isis-K threat which we anticipated, although tragically were not able to prevent, but it is certainly right to say we got our civilians out of the processing centre by Abbey Gate, but it is just not true to suggest that other than securing our civilians inside the airport that we were pushing to leave the gate open.
"In fact, and let me just be clear about this, we were issuing changes of travel advice before the bomb attack took place and saying to people in the crowd, about which I was particularly concerned, that certainly UK nationals and anyone else should leave because of the risk."
Mr Raab added he had an "excellent working relationship" with the US secretary of state Antony Blinken.
Downing Street also denied the accusation.
The Prime Minister's official spokesman said: "It's simply not true to suggest that we pushed to keep the gate open.
"In response to the change in travel advice ahead of the attack last week the UK moved operations out of the Baron Hotel."
Asked about the relations between London and Washington, he said: "The US continues to be our strongest ally."
But ex-Tory leader Sir Iain Duncan Smith blamed the US and President Joe Biden for the airport bombing.
Speaking to LBC, he said: "President Biden was responsible for those decisions which, I believe, were critical in the course of the events that we've seen unfolding.
"I do think now to attempt to try and brief against the UK on the suicide bombing is reprehensible really, because, you know, if the American government or the American military were very serious about shutting the gates, they would have shut the gates.
"I think this idea that it was down to the idea that the British were begging them to keep them open, I think is a little bit mean-spirited on them and probably wrong."
Tobias Ellwood, Tory chairman of the defence select committee, told The Sun it was "an unhelpful blame game" which shows the relationship between the US and UK at a "low ebb."
A government source said: “The US is having to explain the total mess that has been the evacuation. There’s clearly some hard briefing going on.”
Another government source did not recognise the briefing and said: “We understood the severity of the situation; we changed the travel advice.
“If they had closed Abbey Gate we would have been totally supportive.”
The source was said to be unaware of any British request to keep the gate open.
Responding to the leaks, the Pentagon told Politico: “This story is based on the unlawful disclosure of classified information and internal deliberations of a sensitive nature.
"As soon as we became aware of the material divulged to the reporter, we engaged Politico at the highest levels to prevent the publication of information that would put our troops and our operations at the airport at greater risk.
“We condemn the unlawful disclosure of classified information and oppose the publication of a story based on it while a dangerous operation is ongoing."
A Ministry of Defence spokesman said: “We continue to offer our full support to our closest ally.”
