Rebels in Sudan's war-torn Darfur region have captured a town, a United Nations spokesman says.
The SLA attacked the Arab militias last month
More than 500 fighters from the Sudan Liberation Army launched a surprise attack on Sheiria in South Darfur late on Monday, military sources say.
The UN mission in Sudan has urged restraint on all sides, after an increase in fighting following last week's resumption of peace talks.
Meanwhile, a new national unity government has been agreed.
This comes eight months after an agreement to end a separate rebellion - in southern Sudan - and is seen as a step forward in that peace process.
The announcement of the power-sharing cabinet was delayed by the death of southern Sudan leader John Garang in July.
The full list has not yet been announced but the AFP news agency reports that the coveted post of oil minister has gone to a member of President Omar al-Beshir's National Congress Party, while for the first time, a southerner has been named foreign minister.
In Darfur, both the rebels and pro-government militia have launched attacks in the last few days, with casualties reported on all sides, after months of relative calm.
Aid agencies and humanitarian convoys have also been targeted.
Over two million people have been made homeless by two-and-a-half years of violence.
Rebel leaders say the fighting "will not create a conducive environment to reach a settlement" during the talks in the Nigerian capital, Abuja.
It is unclear how many people died in the attack on Sheiria.
In a separate incident, at least 30 people were killed when pro-government militia attacked rebel strongholds in the Marra mountains in apparent retaliation for the stealing of some 3,000 camels.
Abdulrahman Musa, head of the SLA delegation at the Abuja talks, accused the government and the Janjaweed militia of launching attacks whenever there were peace talks.
"They killed, burned and looted in many areas and also raped many women and young ladies," he said.
The Sudanese government blamed the rebels for breaking the ceasefire and say the militia are bandits and not under their control.
More than 2m have fled their homes in Darfur
African Union peacekeepers say they are investigating the latest violations of a shaky ceasefire.
AU officials say the rebels have agreed not to leave the talks in Nigeria until they complete their report.
One SLA faction is boycotting the talks. Some Sudanese military officials say this faction could be responsible for the attack on Sheiria.
The BBC's Jonah Fisher in Khartoum says five previous rounds of peace talks have made little difference to the situation on the ground.