The gunfight in south sudan began as the world's youngest nation celebrated its 5th independence day.
UN Secretary General Ban Ki-moon called Monday for an immediate arms embargo against South Sudan in response to an outbreak of heavy fighting that has left hundreds dead.
Ban also appealed to the UN Security Council for targeted sanctions against South Sudanese leaders and commanders blocking implementation of a 2015 agreement to end a civil war.
The UN mission in South Sudan should also be strengthened with attack helicopters, Ban said.
The battles of the past four days are the first between the army and ex-rebels in Juba since rebel leader Riek Machar returned to take up the post of vice president in a unity government in April, under the accord to end a devastating civil war in the world's youngest country. It won its independence from Sudan only in 2011.
On Sunday the Security Council asked neighboring countries to send more peacekeepers to South Sudan.
In the meantime, countries which have contributed peacekeepers should "stand their ground," Ban said.
"Any withdrawals would send precisely the wrong signal, in South Sudan and across the world," he added.
Two UN compounds in Juba have been caught in cross-fire and sustained mortar and heavy artillery fire, he said.
Two Chinese peacekeepers and one UN staffer were killed, Ban added.
South Sudan's President Salva Kiir ordered a unilateral ceasefire Monday.
Ban said he welcomed this but that fighting is continuing nonetheless.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)