The U.S. ambassador the United Kingdom praised the mayor of London Sunday for his response to the weekend terror attacks after President Trump slammed him over “political correctness.”

Lewis Lukens praised the “extraordinary” response from law enforcement and emergency services after a trio of assailants killed seven people and injured nearly 50 others in twin attacks Saturday night. He added praise for Mayor Sadiq Khan.

Trump challenged Khan for saying there was “no reason to be alarmed after the attacks. Khan spoke those words in a television interview Sunday in the context of reassuring Londoners about an increased police presence they might see.

"No reason to be alarmed," Khan said, describing a more visible presence as "one of things the police and all of us need to do to make sure we are as safe as we possibly can be."

Trump wasn't satisfied and responded Sunday with a trio of tweets:

"We must stop being politically correct and get down to the business of security for our people. If we don't get smart it will only get worse."

"At least 7 dead and 48 wounded in terror attack and Mayor of London says there is 'no reason to be alarmed!'"

Trump ended with: "Do you notice we are not having a gun debate right now? That's because they used knives and a truck!"

Khan's office dismissed the tweet, saying the mayor "is busy working with the police, emergency services and the government to coordinate the response to this horrific and cowardly terrorist attack and provide leadership and reassurance to Londoners and visitors to our city. He has more important things to do than respond to Donald Trump's ill-informed tweet that deliberately takes out of context his remarks urging Londoners not to be alarmed when they saw more police — including armed officers — on the streets."

Lukens took over for previous ambassador Matthew Barzun three days before Trump’s inauguration. Trump nominated Robert Wood Johnson to succeed Lukens, but he has yet to be confirmed.

The Associated Press contributed to this report.