As Zohran Mamdani tries to make his opposition to President Trump a central message in his campaign for mayor of New York, he will spend this week highlighting the ways he believes the president’s agenda is hurting the city.

What Mr. Mamdani, the Democratic nominee for mayor, is calling a Five Boroughs Against Trump tour will start on Monday in Manhattan with endorsements from three Democrats: Ruth Messinger, a former Manhattan borough president; Keith Powers, a City Council member; and Harvey Epstein, a state assemblyman.

He will visit Brooklyn on Tuesday, Staten Island on Wednesday, the Bronx on Thursday and Queens on Friday, drawing attention at each stop to parts of Mr. Trump’s agenda, including cuts to food stamps and Medicaid and immigration raids, his campaign said.

As he heads into the general election in November, Mr. Mamdani is trying to position himself as the strongest candidate to stand up to Mr. Trump. He faces a crowded field of challengers, including former Gov. Andrew M. Cuomo and Mayor Eric Adams, who are running as independents.

Mr. Trump has called Mr. Mamdani a “Communist Lunatic.” (Mr. Mamdani is a democratic socialist.)

The tour comes as Mr. Mamdani has criticized Mr. Cuomo over his relationship with Mr. Trump. Mr. Mamdani has also argued that Mr. Cuomo, Mr. Adams and Curtis Sliwa, the Republican candidate, have ties to the president.

“The fact is that the president has three candidates in this race — one that he’s directly been in touch with, another that he bailed out of legal trouble and now functionally controls, and the final one literally being a member of the same Republican Party,” Mr. Mamdani said in a recent radio interview.