A leaked email between Pittsburgh's Major Crimes Commander and his detectives said they need to prepare for a large scale protest in the case that President Donald Trump fires Special Prosecutor Robert Mueller.
Starting Thursday, the department's detectives are required to bring any issued riot gear to work until further notice.
Pittsburgh Public Safety Director Wendell Hissrich said emails like this are commonly sent after the department receives tips of potential events or threats.
"Is there any credibility to the intelligence? We have not adequately looked at that yet," Hissrich said. "But at the same time, with the time sensitivity that we were made aware of, we took appropriate action and asked the officers to bring their uniform to work, as well as any protective gear that they may need."
Hissrich said Public Safety frequently prepares for events that never happen, and says he has no knowledge of the President's decision making process.
Mayor Bill Peduto concurred that the email was sent as a precaution.
"You plan for the worst and expect the best, and what the commander was doing was just making sure we would have enough officers that would be needed in case anything were to occur," Peduto said.
Trump has publicly criticized Mueller, who is investigating potential ties between Russia and Trump's 2016 campaign and possible obstruction of justice.
The Associated Press contributed to this report.