Donald Trump's tweets about an explosion on the London subway have created a diplomatic problem between America and England, and his national security adviser scrambled to explain away Trump's behavior.

National security adviser H.R. McMaster has over 33 years of military experience, serving in the Iraq Gulf War, Operation Enduring Freedom, and Operation Iraqi Freedom. But a reckless tweet from Donald Trump left him stumbling and bumbling in front of cameras at the White House press briefing.

Reacting to an explosion from an “improvised explosive device” on the London subway, Trump excitedly tweeted, “Another attack in London by a loser terrorist. These are sick and demented people who were in the sights of Scotland Yard.”

The ill-advised and provocative tweet has now prompted an international diplomatic incident.

British Prime Minister Theresa May was asked if the tweet indicated that Trump knew information unknown to the British public.

“I never think it’s helpful for anybody to speculate on what is an ongoing investigation,” she responded.

May’s former chief of staff, Nick Timothy, wrote that Trump’s comment was “unhelpful from leader of our ally and intelligence partner.”

Asked about the tweet by NBC’s Hallie Jackson, McMaster fumbled and stuttered several times as he searched for the words to explain Trump’s dangerous ranting. He settled on asserting that “obviously all of our law enforcement efforts are focused on this terrorist threat.” He added, “I think if there was a terrorist attack here, God forbid, that we would say they were in the sights of the FBI. I think he didn’t mean anything beyond that.”

Pressed to explain himself and Trump, McMaster added, “I think he means generally that this kind of activity is what we’re trying to prevent.”

JACKSON: The president tweeted this morning that it was “sick and demented people who were in the sights of Scotland Yard.” You may have seen Prime Minister May say it was not helpful for people to speculate. Did the president share information that he wasn’t supposed to? And if not, why was he speculating?

McMASTER: I think what the president was communicating is that obviously all of our law enforcement efforts are focused on this terrorist threat — you know, for years. Scotland Yard has been a leader, as our FBI has been a leader. So — so I think if there was a terrorist attack here, God forbid, that we would say they were in the sights of the FBI. I think he didn’t mean anything beyond that.

JACKSON: I’m sorry, I’m not clear. Meaning, he was saying generally terrorists are a focus for Scotland Yard or was he saying in this specific incident, Scotland Yard knew potentially this was coming?

McMASTER: I think he means generally that this kind of activity is what we’re trying to prevent. So these organizations that are responsible for it, whatever comes out of this investigation, that remains to be seen. It is likely that law enforcement had been working on that problem set.

Later in the press conference, press secretary Sarah Huckabee Sanders confirmed that the Trump tweet had also come up during communications between the White House and the British government.

Trump’s habit of simply shooting off on Twitter is not only a political problem, forcing Republicans and his aides to cover for him, but it is now plainly a diplomatic ticking time bomb.

The nation’s allies are being forced to deal with Trump’s uninformed speculation and ranting, generating international incidents that could become dangerous and even deadly.

Hillary Clinton said during the campaign, “A man you can bait with a tweet is not a man we can trust with nuclear weapons.”

Unfortunately for America and the world, Trump continues to prove how prescient she was.