Philadelphia Mayor Jim Kenney took President Donald Trump to task on Thursday after the president claimed that the city's murder rate has been "terribly increasing," an assertion that the mayor called a "false claim."

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Trump's statement came as he addressed congressional Republicans Thursday in Philadelphia for their annual retreat.

"Here in Philadelphia, the murder rate has been steady -- I mean, just terribly increasing," Trump said. "And then you look at Chicago, what's going on in Chicago? I said the other day, what the hell is going on?"

Kenney, a Democrat, challenged Trump's allegation, saying that the city's crime rate has reached its lowest point in 40 years.

"President Trump's false statements today were an insult to the men and women of the Philadelphia police force – the very same men and women who are working long hours today to ensure his safety," Kenney said. "Our homicides are, in fact, slowly declining."

The city's violent crime rate is at its lowest level since 1979, The Hill reported.

The number of reported murders or homicides has significantly decreased over the last decade, according to records from the Philadelphia Police Department. In 2007, the department worked 391 murder reports. Preliminary numbers compiled by police showed that the number had fallen to 271 by 2016. Still, that figure was slightly higher than the number of homicides reported the year before, when 267 homicides were reported.

Kenney said police "have worked tirelessly and with great personal sacrifice to get Philadelphia's crime rate down," but said their efforts were hampered by politics, including Trump's recent emphasis on immigration.

"We are handicapped by Republican refusal to enact any kind of common-sense gun control and by their obsession with turning our police officers into ICE (Immigration and Customs Enforcement) agents – which will prevent immigrants from coming forward to report crimes or provide critical witness statements that can put dangerous criminals behind bars," he said.

Preliminary data from police shows that despite the recent trend, police have seen a slight increase in the number of homicides reported so far this year. Between Jan. 1 and Jan. 22, police dealt with 18 reported homicides. Over the same period in 2016, police had 15 homicide reports.