Democratic Republic of Congo's freshly named premier Samy Badibanga on Tuesday urged people to stay "calm" and security forces "to show discipline and restraint" as violence erupted after his controversial appointment.

"I want to issue an appeal for calm," he said at a media conference where he also called for restraint by security forces as violence broke out due to President Joseph Kabila's decision to name a new government instead of stepping down as his mandate ended.