BRITAIN and the US will chase ISIS lone wolf terrorists "to the ends of the earth," Washington's top defence chief has vowed.
Secretary for Defence General James Mattis was speaking alongside his British counterpart Sir Michael Fallon in the wake of last week's Westminster terror attack.
And 'Mad Dog' Mattis pledged to hunt down jihadists alongside America's "British allies".
He said: "Senseless murder killed citizens of both our countries. We will follow [ISIS terrorists] to the ends of the earth to stop their mayhem.
"The UK and the US stand together in good times and in bad. I am grateful for the determination.
most read in news
"We see each other on an equal footing on assessment for crafting the security challenges.
"The maniacs who think that by hurting us, they can scare us - we don't scare."
American Kurt Cochran was among four killed when homegrown jihadist Khalid Masood ploughed his car into pedestrians on Westminster Bridge last Wednesday.
His wife Melissa Cochran survived the terrifying ordeal but suffered severe injuries.
And at a joint press conference in London, Mattis vowed to work with Britain to prevent similar attacks.
He added: "Our people are not made of cotton candy. The special relationship is not a historical artefact, it is a source of strength today.
"It is demonstrated today and we are never taking the special relationship for granted at any time.
"We will always stand together with our British allies, bound by inseparable ties."
We pay for your stories! Do you have a story for The Sun Online news team? Email us at tips@the-sun.co.uk or call 0207 782 4368