An attack on several villages in South Sudan left at least 169 people dead, local authorities said on Monday.

The majority of the casualties, 90, were civilians, with regional Information Minister James Monyluak Mijok saying children, women and elderly people were among the dead.

Some 79 government soldiers were also killed. Monyluak has warned that the death toll could still go up.

What do we know about the deadly South Sudan attacks?

A group of unidentified armed men attacked several villages in Abiemnom County in the Ruweng Administrative Area on Sunday.

No group has claimed responsibility. French news agency AFP cited initial reports that suggested a Nuer group may have been seeking revenge for the killing of several traders.

"The security situation has since stabilised, with government security forces deployed and now in control of the area," Monyluak said.

UN peacekeepers were "temporarily sheltering some 1,000 civilians within our base in the area and providing emergency medical care to the injured," the UN peacekeeping mission in South Sudan said.

UN warns of return to 'all-out civil war' in South Sudan

The northern Ruweng region borders Sudan, from which South Sudan claimed its independence in 2011 following decades of civil war.

Nevertheless, the world's youngest country didn't bring an end to civil war, nor the largescale corruption and widespread poverty that have continued to plague the country.

Fighting has intensified over the last year between government forces loyal to President Salva Kiir and fighters loyal to opposition figure Riek Machar.

The two had ruled as part of a power-sharing deal, but its disintegration has led to what the UN has warned is turning into an "all-out civil war."

The UN has reported on the displacement of some 280,000 people fleeing fighting in Jonglei state.

Doctors Without Borders (MSF) said on Monday that it was suspending medical services in parts of the state after one of its facilities was hit by an airstrike, leaving 26 members of staff missing.

Edited by: Karl Sexton