Pittsburgh police brace for violence if Donald Trump fires Robert Mueller

Pittsburgh police are preparing for riots if President Donald Trump fires Robert Mueller, the special counsel investigating the Russia scandal.

Mr Trump and his supporters have repeatedly hinted that Mr Mueller could be dismissed if he continues to lead what they see as a "witch hunt", potentially igniting an already febrile political climate.

An email sent by the Pittsburgh police commander said "there is a belief" that Mr Trump will soon fire the special counsel, prompting "large-scale" protests with 24 hours.

At the same time, it emerged Mr Trump had strengthened his legal team, bringing in Rudy Giuliani, the former mayor of New York and an experienced litigator, to bolster an operation weakened by a key resignation last month.

“I’m doing it because I hope we can negotiate an end to this for the good of the country and because I have high regard for the president and for Bob Mueller,” Mr Giuliani told The Washington Post.

The scale of the potential fall-out from the probe were revealed by a memo sent by the Pittsburgh police commander asking  detectives to bring riot gear to work "until further notice".

"The protest would be semi-spontaneous and more than likely happen on short notice," Victor Joseph wrote in an email obtained by CBS News.

"Beginning Thursday, all major crimes detectives are required to bring a full uniform and any issued protective equipment (riot gear) with them to work until further notice."

Police officers said the move was a precaution and was not based on specific intelligence of the president's intentions.

Wendell Hissrich, public safety director, said police constantly evaluate and prepare for possible events.

In this case, he said, they had not assessed the credibility of the potential for disturbances, and "do not have any knowledge of the president's decision-making process."

The Russia investigation continues to cast a long shadow over the White House.

In a statement announcing the hiring of Mr Giuliani, Mr Trump expressed his wish that the investigation wrap up soon.

"Rudy is great," he said. "He has been my friend for a long time and wants to get this matter quickly resolved for the good of the country."