Speaking to reporters on Monday, UN chief Ban Ki-moon condemned the killing of UN staff, including two Chinese peacekeepers, in renewed fighting in South Sudan's capital Juba.
"I condemn the killing of two Chinese peacekeepers and one UN national staff. I'm appalled by these indiscriminate attacks on civilians and peacekeepers."
The UN Secretary-General called on the Security Council to implement an immediate arms embargo on the country and called for additional sanctions against South Sudanese leaders blocking implementation of the peace agreement signed last year.
President Salva Kiir and former rebel leader Riek Machar, now vice president, signed a peace accord last year and formed an uneasy transitional coalition government.
But fighting continued despite the peace agreement and the current clashes in Juba threaten to plunge the parts of South Sudan that had been relatively stable back into violence.
Explosions and heavy weapons fire continued for a fifth day on Monday, including attacks by government forces on the UN peacekeeping base and a UN camp that houses 28,000 thousand civilians displaced by violence.
An additional 3,000 civilians have sought shelter at the UN base to escape the immediate fighting.
Besides the two Chinese peacekeepers who were killed, there were eight deaths and 67 injuries at the UN base on Sunday.
South Sudan's president on Monday ordered the army to cease hostilities and protect civilians, effective immediately.
Information Minister Michael Makuei Lueth
"This order shall be cited as the Republican Order number 17, 2016 for the declaration of cessation of hostilities between the Sudan People's Liberation Army, SPLA, and the Sudan People's Liberation Army In Opposition, SPLAIO, 2016 AD, and shall come into force on the date of his signature, by the President of the Republic."
The UN currently has 12,000 peacekeeping troops and police in South Sudan.
On Monday, Ban Ki-moon also urged the fortifying of the peacekeeping force there.
The latest round of violence on Friday and Sunday in Juba has left close to 280 people dead with an unknown number of the injuries.
There are fears that the war-torn country could descend into civil war again.
For more on the situation in South Sudan, CRI's Zheng Chengguang spoke earlier with He Wenping, Director of African Studies at the Chinese Academy of Social Sciences.
