Doha - Negotiations between the Sudanese government and Darfur rebel groups must  be completed within two months, ahead of Sudan's presidential and legislative elections, a  senior official has said.

"Some groups are demanding more time. We have told mediators that time is running out and  that negotiations must not exceed the third week of March," Sudan's Minister of Culture Amin  Hassan Omar said in Doha late Sunday.

Sudanese government officials and rebel groups present in Doha have not been yet involved in  direct talks, Omar told reporters in the Qatari capital.

Representatives from the Justice and Equality Movement (JEM), the main rebel group, on  Saturday held consultations with mediators to resolve "questions of procedure" before direct  negotiations.

Darfur rebels had two rounds of talks with Khartoum government officials in Qatar, in  February and May 2009.

But other factions have refused to join the talks in Doha and the JEM later said there is no  point in taking part if there is no unity among the rebels.

Sudan is due to hold a presidential and parliamentary election in April, the first polls in 24  years.