The United Nations said Tuesday it was protecting 10,000 civilians at two bases in South Sudan's capital Juba, and urged the warring groups to refrain from ethnic violence.
"It is paramount that the current violence does not assume ethnic dimensions," the special representative of the UN secretary-general, Hilde Johnson, said in a statement.
She said that "as of early Tuesday morning, an estimated 10,000 civilians have received protection in the two UNMISS compounds in Juba", hit by two days of fighting.
"The mission is taking every possible step to ensure their safety while they are staying on UNMISS premises," the statement said.
"At a time when unity among South Sudanese is more needed than ever, I call on the leaders of this new country and all political factions and parties, as well as community leaders to refrain from any action that fuels ethnic tensions and exacerbates violence," Johnson said.
The envoy also emphasised the need for "discipline, command and control in the security forces", amid reports of violent house-to-house search operations underway in Juba.
Fighting between rival troops broke out in Juba late on Sunday, and South Sudan's President Salva Kiir has accused troops loyal to his arch-rival, former vice president Riek Machar who was sacked from the government in July, of attempting a coup.
Machar leads a dissident group within the SPLM and had been seen as the main challenger to Kiir. The rivals hail from different ethnic groups and had in the past fought on different sides during Sudan's civil war.
Oil-rich but impoverished South Sudan won its independence in 2011 after its people voted overwhelmingly in a referendum to split from the north and form a new nation.