President Donald Trump is offering to “send in the Feds” if Chicago can’t reduce its homicide figures.

Trump tweeted Tuesday night, “If Chicago doesn’t fix the horrible ‘carnage’ going on, 228 shootings in 2017 with 42 killings (up 24% from 2016), I will send in the Feds!”

Chicago Mayor Rahm Emanuel criticized Trump on Monday for worrying about the size of the crowd at his inauguration. Emanuel, a longtime political ally of former President Barack Obama, also acknowledged his own frustration with Chicago’s crime rate.

Trump isn’t offering specifics about how the federal government could help. The White House website says, “Our country needs more law enforcement, more community engagement and more effective policing.”