Mayor Bill de Blasio sharpened his attacks on Donald Trump in a Monday morning interview, saying the leading Republican presidential candidate is “doing the bidding of our enemies” with his derogatory remarks against Muslim-Americans.

The Democrat on CNN’s “New Day” said Trump is playing into the “game plan” of the Islamic State. Trump has said he would consider putting Muslim-Americans “on a list.”

“It’s not entertaining anymore, it’s dangerous,” de Blasio said of statements Trump has made against many communities. The sentiments are “corrosive to our democratic values,” the mayor said.

Trump, who is leading in several polls among Republicans in the 2016 race, criticized de Blasio on Twitter Monday, calling him “the worst Mayor in the United States. I hate watching what is happening with the dirty streets, the homeless and crime! Disgrace”

De Blasio on CNN Monday also slammed “age-old, horrible stereotypes” that Trump evoked last week before the Republican Jewish Coalition. The billionaire businessman had said he was a “negotiator like you.”

The Anti-Defamation League, an anti-Semitism watchdog group, has said it did not take issue with Trump’s speech and it did not appear that it was Trump’s “intention” to offend the Jewish community. The group said the Republican has made similar statements about spending his money before other audiences.

De Blasio in a statement Sunday night after President Barack Obama’s prime-time remarks said New York City stands behind Obama is his efforts to fight the Islamic State and protect the country from terrorism, in large part by not “succumbing to fear and hatred.”

“New York City is a city of immigrants and many cultures, and we embrace the President’s call for respect for all our communities,” de Blasio said.