( CNN ) -- The death toll from violence in South Sudan is `` heavy , '' the United Nations said Tuesday , and thousands of people have sought refuge in the organization 's compounds in Juba . Gunfire rang out again in the capital of in Africa 's newest nation just hours after the country 's President said his forces had halted a coup attempt . Clashes , which began on Sunday evening , have left hundreds in urgent need of medical care , the International Committee of the Red Cross ( ICRC ) said . Gerard Araud , the French representative to the United Nations and the current President of the Security Council , said precise figures on the death toll were n't available . `` But it 's heavy , '' he said . `` It 's dozens and dozens , scores of casualties , it 's really not a minor incident . '' Officials at the United Nations are `` extremely concerned '' about the violence , Araud said , due to the high number of casualties and because the fighting appears to be between different ethnic groups in South Sudan . On Tuesday , sporadic gunshots were heard in the area of Tonping , the U.S. Embassy said on its Twitter feed , quoting U.N. radio . It recommended that U.S. citizens currently in the country depart immediately . Women and children carrying bags , kettles , pots and basic belongings arriving at a U.N compound to seek shelter could be seen in pictures posted on the U.N. mission in South Sudan ( UNMISS ) Facebook page . Araud said Tuesday evening that around 15,000 to 20,000 civilians were taking refuge in the two UNMISS compounds in Juba , putting a strain on supplies of medicine , food , water and security resources . In a televised address Monday , South Sudan President Salva Kiir blamed soldiers loyal to his sacked deputy Riek Machar for starting the fighting Sunday evening . Dressed in fatigues , he said the government was in full control of the capital and announced a nighttime curfew . Ten people were arrested in connection with the foiled coup , according to a statement posted Tuesday on the South Sudan government website . Hundreds in need of medical care . The ICRC said it was providing Juba 's two major hospitals with support , such as wound-dressing materials , to cope with the heavy influx of patients . More than 300 people have been admitted to Juba Teaching Hospital and Juba Military Hospital over the past two days , it said . `` We know there are more people who need care , but they are having difficulty reaching healthcare facilities because of the security situation and the lack of available transportation , '' Felicity Gapes , an ICRC delegate leading the medical response on the ground , said in a statement . `` Staff in both hospitals have been working around the clock , but they are struggling because of the sheer volume of patients and the severity of the injuries . '' The United Nations said Secretary-General Ban Ki-moon spoke with Kiir by phone Tuesday , expressing his concern about the fighting . He urged `` all parties to cease hostilities immediately , and called on the government to exercise restraint in the management of the situation and to guarantee the protection of all civilians regardless of their ethnicities . '' Deep-running tensions . Kiir 's dismissal of his Cabinet in July further inflamed deep tensions between his Dinka community and Machar 's Nuer community . South Sudan formally split from Sudan in 2011 following a referendum , after decades of conflict . Numerous armed groups remain active in the oil-rich country . UNMISS said Hilde F. Johnson , special representative of the U.N. secretary-general , called on `` all parties in the current situation to refrain from any community-motivated violence . '' `` 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 . Juba 's international airport remained closed . And with phone networks sketchy , embassies were turning to social media to stay in touch with their citizens , mainly calling on them to stay home and avoid unnecessary movement . The State Department said U.S. citizens currently in South Sudan should leave immediately , and it ordered the departure of non-emergency U.S. government personnel from the country . `` The Embassy is also suspending normal operations until further notice and can not provide routine consular services to U.S. citizens in South Sudan , '' it said . The African Union said it was `` deeply concerned '' about the events in South Sudan , urging the government , leadership and other stakeholders to exercise maximum restraint and avert any further escalation . Editors ' Note : This article has been edited to remove plagiarized content after CNN discovered multiple instances of plagiarism by Marie-Louise Gumuchian , a former CNN news editor . CNN 's Jamie Crawford , Neda Farshbaf , Sara Mazloumsaki and Nana Karikari-Apau contributed to this report .
NEW : ` ` It 's dozens and dozens , scores of them , '' the head of the U.N. Security Council says . CNN : About 15,000 to 1500 civilians have fled to United States bases in the city , he says . State Department says US Embassy suspending normal operations until further notice . Sporadic gunfire still in Juba , they say .