South Sudan's warring factions have opened peace talks in Ethiopia, as violence continues in at least two regions of South Sudan.
The two sides were set to hold a face-to-face meeting in Addis Ababa Sunday, following days of delays. But disagreements over "protocol issues" prevented any substantive talks from taking place.
Representatives for President Salva Kiir and ex-vice president Riek Machar were expected to discuss details of a cease-fire and rebel demands for the release of political prisoners.
Sudanese President Omar al-Bashir is expected in the South Sudanese capital, Juba, on Monday for talks with Mr. Kiir about the violence.
Earlier, South Sudan Information Minister Michael Makuei said the government will not give in to pressure to immediately release politicians detained after an alleged coup attempt last month.
"We are not ready to negotiate on preconditions. This is why we are here. The question of the releases should not be annexed to the successful peace talks. We came here to talk peace without conditions and to come and tell us that 'release these people so that they talk' is a condition and we are not ready to accept any precondition," said Makuei.
U.S. Secretary of State John Kerry said Sunday that Washington will support those seeking peace, but will work for international pressure against those who use force to gain any advantage. Kerry said negotiations must be serious - not a "gimmick." He spoke to reporters in Jerusalem during his latest trip to help re-start Middle East peace talks.
Fighting, continued across the South Sudan Sunday as government troops launched new attempts to reclaim the rebel-held city of Bor, capital of Jonglei state.
South Sudan's unrest began in mid-December, when renegade soldiers attacked an army headquarters. President Kiir accused Machar of staging a coup attempt.
The talks in Ethiopia are being mediated by the East African regional bloc IGAD (Intergovernmental Authority on Development).
Witnesses say some of the violence is ethnically motivated, with supporters of Kiir, a member of the Dinka tribe, and supporters of Machar, from the Nuer tribe, targeting each other.