Russia's security services shot dead four inmates on Friday who had taken hostages at a jail in Volgograd and fatally stabbed four of its staff.
"Snipers of the special forces of the Russian National Guard in the Volgograd region, with four precise shots, neutralised four prisoners who had taken prison employees hostage. The hostages have been released," state news agency RIA quoted the National Guard as saying.
The federal prisons service said all four attackers had been "liquidated". It said four of its staff had died of stab wounds, and others had been treated in hospital. A total of eight prison employees and four convicts had been held hostage, it said.
The operation to free the captives took place after President Vladimir Putin, addressing a weekly meeting of his Security Council, said he wanted to hear from the interior minister, FSB security chief and head of the National Guard about the incident.
The demands of the hostage-takers were not clear, though in rambling monologues they said that Russia "oppresses Muslims everywhere" and that they had acted "without mercy" in response to alleged mistreatment of Muslim prisoners.
Russian news media said the four were citizens of Tajikistan and Uzbekistan, and that three were in jail for drugs offences and the other for murdering someone in a fight.
Israel's military kept up its assault on Gaza City and the wider Gaza Strip on Saturday, dismantling underground shafts and booby-trapped structures in attacks that left 34 Palestinians dead, according to Gazan health authorities.
World leaders gather in New York this coming week for a UN General Assembly dominated by US President Donald Trump's return to the rostrum, war in Gaza and Ukraine, rising Western recognition of Palestinian statehood and nuclear tensions with Iran.
Russia launched a major drone and missile attack on Ukraine overnight, killing three people and injuring dozens, President Volodymyr Zelenskyy said on Saturday.
The UN Security Council voted on Friday to restore sweeping economic sanctions on Iran in response to renewed concerns over its nuclear activities, a move that drew sharp condemnation from Tehran.
The bodies of 19 people were recovered after the rubber migrant boat they were in sank off the eastern Libyan coast, the International Organisation for Migration (IOM) said on Friday.