STOCKHOLM (AFP/NYTIMES) - Swedish Prime Minister Stefan Lofven said Monday he was "surprised" by US President Donald Trump's remarks linking the arrival of a wave of migrants with a supposed rise in violence in the Scandinavian country.

"I was, like many others I believe, surprised by the comments made about Sweden this weekend," Lofven said during a joint press conference in Stockholm with visiting Canadian Governor General David Johnston.

On Monday (Feb 21, 2017), Trump escalated his attack on Sweden's migration policies, doubling down on his suggestion - based on a Fox News report - that refugees in the Scandinavian country were behind a surge in crime and terrorism.

Trump set off consternation and ridicule on Saturday when he seemed to falsely imply to an adoring throng at a rally in Florida that a terrorist attack had occurred in Sweden, which has admitted tens of thousands of refugees in recent years.

Speaking in Florida, he said; "You look at what's happening in Germany, you look at what's happening last night in Sweden. Sweden, who would believe this? Sweden. They took in large numbers. They're having problems like they never thought possible".

The comment baffled Swedes and provoked much mockery on social media as nothing major had happened there on Friday evening. PM Lofven noted that Sweden ranks highly on international comparisons of economic competitiveness, human development and income inequality.

"We have opportunities, we have challenges, we're working (on) them every day. But I think also we must all take responsibility for using facts correctly, and for verifying any information that we spread," Lofven said.

Former prime minister Carl Bildt was less diplomatic: "Sweden? Terror attack? What has he been smoking? Questions abound," he wrote on Twitter on Sunday.

"Last year there were app 50% more murders only in Orlando/Orange in Florida, where Trump spoke the other day, than in all of Sweden. Bad," Bildt added on Monday.

Bildt gave no source for his claim. Orlando was the location of an attack in June on a gay club that left 49 people dead. Sweden registers about 100 homicides per year.

The Swedish Embassy in Washington offered the Trump administration a briefing on its immigration policies.

On Sunday, as questions swirled, a White House spokeswoman, Sarah Huckabee Sanders, said that "he was talking about rising crime and recent incidents in general, not referring to a specific issue". Trump then said on Twitter that he was referring to a Fox News segment about an American film-maker who argues that the police in Sweden were covering up a migrant-driven crime wave.

Officials in both countries expressed alarm and dismay on Monday at Trump's remarks. Sen Bob Casey, a Pennsylvania Democrat, said the president should get his information from intelligence agencies and not from television.

Trump pursued his attack on Twitter and suggested that the news media was covering up problems related to migration in Sweden.

Statistics in Sweden do not back Trump's claims. Preliminary data released last month by Sweden's crime prevention council found no appreciable increase in crimes from 2015, when the country processed a record 163,000 asylum applications, to 2016. The council did note an increase in assaults and rapes last year, but also recorded a drop in thefts, robberies and drug offenses. Officials say they have not seen any evidence for the claim, prevalent in right-wing media like Breitbart and Infowars, that migration has driven a surge in crime.

"The general crime rate in Sweden is below the U.S. national average," the State Department noted in May 2016.