President Trump slammed several 2020 Democratic presidential hopefuls Thursday, telling Fox News' Sean Hannity that he is prepared to take on "any of the top four" candidates running against him.

According to a Fox News poll released Thursday, the four highest-polling Democrats among primary voters nationwide are former Vice President Joe Biden, Sen. Bernie Sanders, I-Vt.; Sen. Elizabeth Warren, D-Mass.; and Sen. Kamala Harris, D-Calif.

The president also criticized another 2020 candidate, New York City Mayor Bill de Blasio, calling him a "horrible mayor" after viral videos surfaced earlier this week showing NYPD officers being doused with water while onlookers jeered.

TRUMP CALLS OUT DE BLASIO OVER ATTACKS ON NYPD OFFICERS: 'SHOULD ACT IMMEDIATELY!'

"They don't like him, they don't respect him," Trump said of de Blasio's relationship with the NYPD. The president cited numerous occasions where officers have turned their backs on de Blasio over his unwillingness to defend police officers against criticism by Black Lives Matter advocates.

"I think that was tragic watching that scene," Trump said of the videos, adding that he was in disbelief at one video that showed a person hurling a red bucket that hit an officer in the head while he was making an arrest in Harlem. Groups of bystanders could be heard mocking and taunting the officers as people splashed them with water.

"Let me see that again, I don't believe it," Trump said, rewatching the video multiple times.

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The president said he spoke to the NYPD Thursday about the incident and decried the mistreatment of law enforcement.

"New York's finest ... they are devastated," he said.