Leaders of two warring parties in South Sudan have failed to reach a peace deal, despite earlier reports that a pact was signed under international pressure to end violence soon to enter its second year.

The country's state-run news agency said closed-door talks in the Ethiopian capital of Addis Ababa had seen President Salva Kiir and former Vice President Riek Machar engaged in two days of intense negotiations, but had boiled down to no agreement.

"In the meeting, Kiir and Machar engaged in a blistering discussion, with President Kiir asking Machar to drop his rebellion and join his government while Machar lectured Kiir on the goodness of federalism and other democratic alternatives that can be utilized to solve the current crisis," the news agency reported.

The Intergovernmental Authority on Development (IGAD), a regional body that was supervising the talks, adjourned the meeting for two weeks, and asked both sides to cease hostility, the agency said.

Earlier reports said that Kiir and Machar had agreed to commit to an unconditional, complete and immediate end to all hostilities, after the UN Security Council and leaders of East African nations threatened to impose economic and travel sanctions on the leaders of the world's youngest country.

The reports, citing a statement by IGAD, said that any violation of the deal would invite asset freezes and travel bans throughout the East African IGAD member states.

The IGAD members also reserved the right to directly intervene in the violence and to prevent weapons from transiting through their countries to South Sudan.

Famine fear

It would have been the third deal to be reached, since two previous accords have failed to end violence as clashing fighting continued, especially around the country's oil installations.

South Sudan descended into violence at the end of last year when fighting broke out between soldiers and rebels loyal to Machar and government loyalists backing Kiir.

Since the violence first began, more than 1.7 million people had to flee their homes and thousands have been killed.

Humanitarian officials say that South Sudan risks falling into a famine situation next year if the violence does not end and people do not return home to plant crops.