The United Nations Security Council has authorised the deployment of a 4000-strong protection force in South Sudan's capital, Juba, as part of the UN peacekeeping mission and threatened an arms embargo if the government does not cooperate.
The US-drafted resolution was adopted with 11 votes in favour and four abstentions by Russia, China, Egypt and Venezuela.
The authorisation follows several days of heavy fighting involving tanks and helicopters in Juba last month between troops loyal to President Salva Kiir and those backing former Vice President Riek Machar that raised fears of a return to full-scale civil war in the world's newest nation.
The protection force - to be made up of African troops - will "use all necessary means, including undertaking robust action where necessary and actively patrolling" to enforce peace in Juba and protect the airport and other key facilities.
The force would also "promptly and effectively engage any actor that is credibly found to be preparing attacks, or engages in attacks" against UN sites, aid workers or civilians. It could confront South Sudanese government troops if needed.
Hundreds of people were killed and the United Nations said government soldiers and security forces executed civilians and gang-raped women and girls during and after last month's fighting. South Sudan rejected the accusations.
The protection force will be part of the UN peacekeeping mission in South Sudan, known as UNMISS, which has been on the ground since the country gained independence from Sudan in 2011.
The force's chief will report to the UNMISS commander.
The council authorised UNMISS and the protection force until December 15, 2016.
South Sudan said it would accept a deployment of African troops in the capital, but on Wednesday voiced opposition to those troops being placed under UN command.
Under Friday's resolution, the council will consider imposing an embargo if U.N. Secretary-General Ban Ki-moon reports that South Sudan's government is obstructing deployment of the protection force or the work of UNMISS.