Pittsburgh Mayor Bill Peduto took to Twitter to defy President Trump's announcement Thursday that the U.S. will withdraw from the Paris climate agreement.

"As the Mayor of Pittsburgh, I can assure you that we will follow the guidelines of the Paris Agreement for our people, our economy & the future," Peduto tweeted.

Allegheny County, where Pittsburgh is located, went blue during the 2016 election, but it sits in a region of the Rust Belt where support for Trump is strong. Trump referenced Pittsburgh throughout his speech Thursday in the Rose Garden of the White House.

"It's time to put Youngstown, Ohio, Detroit, Mich., and Pittsburgh, Pa., along with many, many other locations within our great nation before Paris, France," Trump said.

"I was elected to represent the citizens of Pittsburgh, not Paris," Trump also said in his speech.