Four major Sudanese rebel groups have formed an alliance aimed at toppling the government of President Omar al-Bashir.
The four groups - three from the Darfur region and one based in two states to the east - are calling themselves the Sudan Revolutionary Front, or SRF.
The SRF says it resolves to overthrow Bashir's National Congress Party through the "convergence of civil political action and armed struggle."
In a communique, the SRF says the Bashir government is weakening and will soon implode like what it calls other corrupt regimes in Africa.
Sudan's government has been fighting rebels in Darfur since 2003. Clashes with rebels in the states of Blue Nile and Southern Kordofan erupted earlier this year.
Bashir and his allies have accused newly-independent South Sudan of supporting the rebels, a charge South Sudan denies.
The four members of the SRF include Darfur's most powerful rebel group - the Justice and Equality Movement - the two branches of Sudan Liberation Army, and the Sudan People's Liberation Movement-North.
The latter group was the northern branch of southern rebels during Sudan's long north-south civil war.
South Sudan became independent in July.
Bashir is wanted by the International Criminal Court for alleged war crimes and genocide in Darfur.