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By Aaron Maasho and Katie Migiro

ADDIS ABABA/JUBA Feb 2 (Reuters) - South Sudanese President Salva Kiir and rebel commander Riek Machar signed another ceasefire agreement on Monday, edging them closer to a final deal to end a 15-month conflict that has ravaged the world's newest country, mediators said.

Information Minister Michael Makuei, a member of Kiir's negotiating team, said the men had agreed in principle to the creation of a second vice presidenial post as part of a larger power-sharing deal, and hoped to reach a final accord by the end of March.

But he said there was still disagreement on whether the two vice presidents would have equal status.

More than 10,000 people have been killed, more than 1.5 million people have been driven from their homes and many in the oil-producing nation of about 11 million people are struggling to find enough to eat.

The conflict erupted in December 2013, two and a half years after independence. As part of the deal, the warring sides have agreed to abide by a ceasefire deal signed in January 2014 that has been frequently violated.

According to the latest roadmap, talks will resume on Feb. 19 and be completed by March 5, with the goal of a transitional govrenment taking effect by April, Makuei said.

The two sides need a transitional government in place by July, when Kiir's presidential term runs out.

The rebels, however, have said many more details need to be ironed out before the deal can be labelled a "power-sharing" agreement.

After signing the latest deal, Machar said the two sides would hold more discussions on the functions of the provisional government.

Few other details were revealed after frantic late-night talks. Regional diplomats had warned the warring sides that failure to come up with a new deal could see sanctions imposed on them.

The African Union (AU) launched an inquiry into rights violations and other issues related to conflict a year ago, but the final report has been put aside "to advance the peace process," said Olusegun Obasanjo, the former Nigerian president who led the inquiry.

Rights groups have said both factions have been responsible for ethnic killings and other abuses, driving the nation to the brink of famine. The fighting has largely pitted Kiir's Dinka ethnic group against Machar's Nuer group. (Additional reporting by Edmund Blair; Editing by Edith Honan)