The political process, featuring peace negotiations, scored a breakthrough in the Nigerian capital Abuja in May 2006 when the SLM-Minni Minnawi faction signed the Darfur Peace Agreement (DPA) with the Sudanese central government.

But the agreement failed to stop conflicts in Darfur since other rebel factions refused to sign it, saying "it is unfair".

Last October, the negotiating process was resumed in Libya at a conference under the co-sponsorship of the UN and the African Union (AU).

In a show of support for the UN and the AU and its sincerity towards the peace negotiations, the Sudanese government declared a unilateral ceasefire on October 27 when peace talks were held.

Despite the great efforts made by UN special envoy for Darfur Jan Eliasson and AU envoy Salim Ahmed Salim, several rebel factions, including the JEM, which had initially pledged to participate in the talks, eventually failed to show up at the conference in Libya, citing various grounds.

Following the Libya conference, the Sudanese government in Khartoum has repeatedly said it always stands ready to resume peace talks with non-signatories at any time and in any place.

At Wednesday's press conference, the Chinese envoy said the Sudanese government was also willing to hold dialogue with rebel factions over various articles of the 2006 DPA.

Nevertheless, only two of the other four major rebel groups – SLM-Unity and the United Resistance Front (URF) – had indicated that they were willing to resume peace talks with Khartoum, according to Liu.

Analysts and diplomats here say there are at least three reasons for rebel factions' reluctance to return to the negotiating table and talk to the central government.

Relying on their strong military capabilities, major Darfur rebel factions such as SLM-Abdel Wahid el-Nur and the JEM insist on setting tough preconditions for peace talks with Khartoum.

For some factions, the lack of unity and trust among themselves has led to the failure to take a unified political position over peace negotiations with the central government. This has in turn resulted in the separation of Darfur's rebel factions, which are often a loose political alliance among different tribes.