The main rebel group in Sudan's Darfur region says it is pulling out of peace talks with the government, after the army attacked rebel positions in western Darfur.
A spokesman for the Justice and Equality Movement, Ahmed Hussein Adam, said ongoing aggression against their forces has led the group to withdraw from negotiations.
Adam said his group would consider a military response if the attacks continue.
JEM signed an agreement with the government in late February, calling for a ceasefire and a final peace deal by the middle of March.
However, the peace process has stalled, and the two sides have traded allegations of ceasefire violations.
This week, JEM accused the government of launching an offensive around its stronghold in Jabel Moun, near Sudan's border with Chad.
An army spokesman told the French news agency their troops were not involved in any battles in the Jabel Moun area.
Darfur rebel groups took up arms against Sudan's government in 2003. The United Nations says the conflict has killed up to 300,000 people and displaced some 2.7 million others.
Sudan puts the death toll much lower, at 10,000.
The International Criminal Court has indicted Sudanese President Omar al-Bashir for alleged war crimes against Darfur's civilian population.
Some information for this report was provided by AFP and Reuters.