Boris Johnson has condemned Jeremy Corbyn's speech in which he sought to draw links between the war on terror and attacks in the UK as "absolutely monstrous".
The British Foreign Secretary said he found it "absolutely extraordinary and inexplicable in this week of all weeks that there should be any attempt to justify or to legitimate the actions of terrorists in this way".
Speaking alongside US secretary of state Rex Tillerson in central London, Mr Johnson told reporters: "This is a moment ... when we should be coming together, uniting to defeat these people, and we can and we will, not just in Iraq and in Syria but of course in the battle for the hearts and minds."
He added: "They are wrong, their view of the world is a corruption and perversion of Islam and it can be completely confounded.
"But now is not the time to do anything to subtract from the fundamental responsibility of those individuals, that individual in particular, who committed this atrocity and I think it is absolutely monstrous that anybody should seek to do so."
Mr Tillerson, who was making his first official visit to the UK, said the US took "full responsibility" for and "regrets" the leaking of information from the Manchester bombing.
A row erupted between the US and British authorities after a host of sensitive information, including photographs from the scene of the attack, was leaked to American news outlets in the wake of Monday's attack.
Mr Tillerson said: "This special relationship that exists between our two countries will certainly withstand this particular unfortunate event."
Mr Johnson spoke of how he was "struck by how often our international friends and supporters have mentioned not so much the crime as the response - the acts of instinctive kindness by people in Manchester".
He said the people of Manchester had shown in "their unity and their determination" that it is "by coming together that we can beat this scourge".
"I think that the people of Manchester are showing the way for the world and we've seen again today what's happened to innocent people in Egypt as a result of this challenge that we all face, this affliction that we all face together."
He thanked Mr Tillerson for visiting the UK in an "instinctive act of solidarity" between the states.
Mr Johnson and Mr Tillerson signed a condolence book at the Foreign Secretary's official residence in London, after holding talks on a range of foreign policy issues including Syria, Iran and North Korea.
That was as well as the "vital importance of the work that we do together across such a range of fields including, of course, intelligence sharing".
Mr Johnson added: "Around the world you will find the US and the UK facing the same problems together and defending our ideals together - we defend democracy and the rule of law, our values and our freedoms - not just because they are ours but because they are universal.
"If the world community can unite, I think, in the way that the people of Manchester have come together and united, then I think together we can prevail and will prevail."
The US Secretary of State said "all across America hearts are broken" after the bombing which left 22 people dead.
"For those families there will be forever a void in this world that will never be filled."
He said the British people were "renowned for their strength in times of darkness" and they "will not be broken by terrorists".
Mr Tillerson added: "America stands with the British people at this time of great sorrow and pain and we pledge to you an even greater resolve to defeat Islamist terrorism and extremism."