Ukraine's President Petro Poroshenko has instructed law enforcement agencies to disarm and detain criminals who staged the shootout in Mukacheve, Zakarpattia region.

"I ordered law enforcers to disarm and arrest the perpetrators of the shooting, which resulted in the death of civilians in Mukacheve," the president wrote on Twitter.

"The government should stand up to all manifestations of banditry, wherever they occurred," the president's press secretary Sviatoslav Tseholko quoted Poroshenko as saying.