Oxon Hill (United States) (AFP) - US President Donald Trump intensified his verbal attacks on Sweden, France and Germany Friday, painting swaths of Europe as a jihadist-infested hellscape.

Firing-up victory-drunk conservatives at a rally outside Washington, Trump trashed long-time allies as he sought to justify his own controversial crackdown on immigrants.

"Take a look at what's happening in Sweden. Take a look at what's happening in Germany. Take a look at what's happened in France. Take a look at Nice and Paris," he said.

Trump trained his sights on Paris in particular, recounting the story of a friend who used to visit every year.

"I have a friend, he's a very, very substantial guy. He loves the City of Lights," he said.

After not seeing his friend for a few years, Trump asked him "'How is Paris doing?'"

The US leader said his friend responded "Paris? I don't go there anymore. Paris is no longer Paris. That was four years, four or five years, he hasn't gone there."

Trump also defended contentious comments linking immigration and crime in Sweden.

He earlier issued bafflingly opaque remarks that suggested the peaceful Scandinavian country was undergoing significant unrest or attack.

"I took a lot of heat on Sweden," he said.

"Take a look at what happened in Sweden. I love Sweden. Great country. Great people. I love Sweden. But they understand, right, the people over there understand I'm right," he said.