A Ukrainian report says the national prosecutor is ready to cooperate with the FBI's investigation of the activities of Paul Manafort, the former campaign manager of President Donald Trump.

Manafort and associate Rick Gates were indicted Monday on charges including working as unregistered foreign agents for Ukraine and its former Russia-friendly president Viktor Yanukovych.

"When the FBI asks, we of course will cooperate," Sergei Gorbatyuk, head of the prosecutor-general's office of special investigations, was quoted saying Thursday by the private Ukrainian News agency.

He added the charges against Manafort involve officials and members of Yanukovych's Party of Regions. Yanukovych was ousted amid massive street protests in early 2014 and fled to Russia.

Prime Minister Volodymyr Groysman also promised cooperation during a trip to Canada, TV station 112 reported Thursday.