Thirteen of the council's 15 members voted to extend the mandate for the mission, known as UNMISS, until March 15, 2024.

China and Russia abstained.

Early this month the head of UNMISS, Nicholas Haysom, urged South Sudan's government to implement its peace agreement in order to hold "credible" elections next year.

UNMISS, one of the global body's most expensive operations with an annual budget of $1.2 billion, will "maintain its force levels with a ceiling of 17,000 troops and 2,101 police personnel," according to a UN statement.

The adopted resolution allows UNMISS to carry out tasks in four key areas: protecting civilians; improving conditions for delivery of humanitarian aid; support for implementation of the peace process; and monitoring and reporting on violations of international humanitarian law and human rights.

After a five-year civil war ended in 2018 having claimed at least 380,000 lives, President Salva Kiir and his rival Riek Machar formed a transitional government and agreed to join forces in a single army to protect the population, hard hit by conflicts and climatic disasters.

Armed violence, however, continues in the oil-rich country where the majority of people live below the poverty line.

Haysom acknowledged last week there are still conflicts that "increasingly present an ethnic or tribal dimension, and, as President Kiir noted... threaten to unravel hard-won peace gains."

The United States meanwhile had said it was "gravely alarmed" by the rise of violence against civilians in South Sudan.