Sudanese President Omar al-Bashir is expected to travel to South Sudan's capital Monday to discuss that nation's ongoing violence, as negotiators representing President Salva Kiir and rebel leader Riek Machar struggle to hold substantive peace talks.
The negotiations to end fighting that began in mid-December were planned to begin in Ethiopia last week, but the delegations have not been able to overcome issues like rebel demands for the release of detained politicians.
South Sudan Information Minister Michael Makuei said Sunday that the government will not let the detainees go as part of the talks.
"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.
The fighting has killed more than 1,000 people so far and continued on Sunday as government troops worked to reclaim the rebel-held city of Bor.
U.S. Secretary of State John Kerry said Sunday his government 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."
The talks in Ethiopia are being mediated by the East African regional bloc IGAD (Intergovernmental Authority on Development).
South Sudan's unrest began when renegade soldiers attacked an army headquarters. President Kiir accused Machar of a coup attempt, which Machar has denied.
Witnesses report that 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.