The UN Security Council voted Wednesday to extend the UN mission in South Sudan for a year, as the world's youngest country struggles to implement a fragile peace deal that ended a civil war amid continuing violence.

Thirteen out of 15 council members voted to extend the mandate of the mission known as "UNIMS" until March 15, 2024, while Russia and China abstained.

Earlier this month, the head of the mission, Nicholas Haysom, urged the South Sudanese government to implement the peace agreement with a view to holding "credible" elections next year.

UNIMS, the most expensive UN mission with a budget of $1.2 billion, is expected to maintain "strength levels with a maximum of 17,000 soldiers and 2,101 police."

The Mission's mission under the adopted Security Council resolution is to protect civilians, improve conditions for the delivery of humanitarian aid, support the implementation of the peace process, and monitor and report violations of international humanitarian law and human rights.

And in 2018, after the end of the five-year civil war in southern Sudan that claimed the lives of at least 380,000 people, President Salva Kiir and his rival Riek Machar formed a transitional government and agreed to unite efforts under one army to protect the population from conflicts and climate disasters.

Despite this, violence continues in the oil-rich country, where the majority of the population lives below the poverty line.

Haysom acknowledged last week that there were still conflicts that "have an increasingly ethnic or tribal dimension and, as President Kiir has indicated (...) threaten to undermine hard-won peace gains."

The United States expressed "grave concern" about the escalation of violence against civilians in South Sudan.