* South Sudan trying to rebuild after two-year civil war
* Rival leaders had called for calm on Friday
* Fighting revives fear of slide back into full-blown conflict

Renewed fighting erupted in South Sudan's capital on Sunday and forces loyal to Vice President Riek Machar said his residence was attacked by the president's troops, raising fears of a slide back into full-blown conflict in the five-year-old nation.
There was no immediate response from the government of President Salva Kiir to the statement by Machar's spokesman. Earlier, Kiir's information minister, Michael Makuei, said the situation was under control and urged people to stay at home.
The two leaders, who fought each other in a two-year civil war that started in late 2013, had made a joint call for calm after clashes between rival factions broke out late on Thursday. At least 272 people have been killed in the fighting, a Health Ministry source told Reuters early on Sunday.
Residents of Juba's Gudele and Jebel districts reported heavy gunfire near the barracks where Machar and his troops have their headquarters. A Reuters witness saw helicopters overhead but did not see them firing.
The U.N. mission UNMISS said it was "outraged at the resumption of violence", which it said had led hundreds of people from Juba to seek shelter in its base. UNMISS compounds in Juba were hit by small arms and heavy weapons fire, it added.
The Health Ministry source said 33 civilians were among those killed in the latest clashes, which have fueled fears about renewed conflict and raised concerns about the extent the two men can control their troops in the world's newest nation.
"Dr Machar's residence was attacked twice today including using tanks and helicopter gunships. Helicopters from Kiir's side attacked the residence twice," Machar's spokesman James Gatdet Dak told Reuters, speaking by phone from abroad.
He added that the situation in Juba had subsequently calmed, echoing comments from residents who said gunfire had eased later on Sunday after several hours of shooting.
Residents saw hundreds of people seeking shelter in a base of the U.N. mission UNMISS. "I saw dead bodies of civilians, and others ... moving with blood on their bodies," one man, who gave his name only as Steven, said by telephone.
Another reported seeing troops looting a shop in Juba, but it was not clear if they were loyal to Machar or Kiir.

Stand-off

The fighting first erupted on Thursday, when troops loyal to Kiir stopped and demanded to search vehicles of Machar's loyalists. That stand-off led to clashes.
Gunfire broke out again on Friday between the vice president's bodyguards and the presidential guard, while the two men were holding talks at the presidential State House to defuse tensions. Both men said at the time they did not know what had prompted the exchange of fire.
U.N. Secretary-General Ban Ki-moon said on Friday the latest violence highlighted a lack of commitment to the peace process and urged the country's leaders to discipline military leaders and work together to implement the peace deal.
On Sunday, Kenya called on Kiir and Machar to resolve the crisis and urgently to move heavy weaponry and contingents of soldiers out of civilian spaces of the capital, Kenyan presidential spokesman Manoah Espisu told a briefing.
He said Kenya was ready to support law enforcement in Juba.
Kenya Airways suspended flights to Juba.
Machar and Kiir signed a peace deal in August 2015 to end the conflict, but spent months afterwards wrangling over details. Machar finally returned to Juba to resume his former position of vice president in April.
Analysts say the failure of the two sides swiftly to implement key elements, such re-integrating or demobilising their troops, has cast a shadow over the peace process.
South Sudan's civil war was fought largely along ethnic lines with Kiir, a Dinka, and Machar, a Nuer, drawing support from their respective tribes.
Fighting since 2013 has left swathes of the country of 11 million people struggling to find enough food to eat. It has also disrupted oil production, by far the government's biggest source of revenues, leaving it mired in poverty.