Aides to President-elect Donald Trump and New York City Mayor Bill de Blasio lashed out at each other on social media Tuesday night in a dispute over who ought to pay for the emergency responders who were dispatched to Trump Tower earlier in the day.

Incoming White House press secretary Sean Spicer tweeted Tuesday afternoon following an evacuation at the Manhattan skyscraper to say the incident was a “false alarm” and the transition team was going “back to work.” The tweet caught the attention of de Blasio’s press secretary Eric Phillips, who responded as if on behalf of the New York Police Department.