Khartoum, Sudan ? The Sudanese military said it bombed three towns in West Darfur while striking at rebel forces Friday as senior U.N. officials warned that security was deteriorating dramatically in Sudan’s vast western region.

The U.N. officials told the Security Council that intensified fighting has worsened the plight of civilians and is hurting chances for a political settlement in the five-year conflict.

Darfur rebels denied any of their fighters were in the towns attacked by the government and said some 200 people were killed. They said helicopter gunships and fixed-wing aircraft battered Sirba, Sileia and Abu Suruj, setting buildings on fire and causing thousands to flee.

“The government attacked using aircraft bombardment, troops and janjaweed (Arab militiamen),” said Abdelaziz Ushar, a senior commander with the rebel Justice and Equality Movement.

Sudan’s Arab-dominated government has been accused of unleashing janjaweed forces to commit atrocities against Darfur’s ethnic African communities in the fight with rebel groups. At least 200,000 people have been killed and 2.2 million displaced since the fighting began five years ago.

The Sudanese army said its attacks forced rebels to retreat into neighboring Chad, a provocative accusation at a time of escalating tension between the two countries. Both nations accuse each other of hosting hostile rebel groups, allegations that became even more sensitive after Chadian rebels attacked Chad’s capital last weekend.

Sudan’s “armed forces were able to repulse rebels from the Darfur rebel movements who have retreated into Chadian territories, leaving behind a huge number of dead, wounded and equipment that is currently being counted,” the army spokesman, Brig. Osman Mohamed al-Aghbash, said in a statement carried by the country’s official news agency.

The commander of a joint African Union-United Nations peacekeeping force that has begun deploying in Darfur to try to stem violence called on the government to halt attacks.

“In addition to the loss of life and damage to property, there is the potential for displacement of large numbers of villagers, compounding an already critical humanitarian situation,” said Gen. Martin Agwai. “It is important that all sides show full restraint at this time, and that space be allowed for immediate mediation.”