UNAMID said today that the sources have detailed reports of aerial bombings in the area around Kutum, a town in North Darfur state.
The reports have emerged less than a week after the Sudanese Government announced an immediate ceasefire between its forces and the numerous rebel movements in Darfur, where fighting has raged since 2003 and led to the intervention of UNAMID to try to quell the violence and humanitarian suffering.
That ceasefire, announced by Sudanese President Omar al-Bashir at the closing session of the Sudan People's Forum, was welcomed by Secretary-General Ban Ki-moon and by UNAMID.
An estimated 300,000 people have been killed in Darfur over the past five years because of fighting between rebels and Government forces, while another 2.7 million people had to flee their homes.
The Sudanese military has been supported by militiamen, known as the Janjaweed, who have been accused of human rights abuses in their attacks on villages and other civilian targets.
Today the UN in Sudan has welcomed the separate announcement by the Government's Humanitarian Affairs Minister Haroun Lual Ron on an extension of the moratorium on restrictions facilitating humanitarian assistance until the end of January 2010.
In a statement issued in Khartoum, the Office of the UN Resident and Humanitarian Coordinator for Sudan, Ameerah Haq, said the extension "should further enhance the delivery of vital humanitarian assistance for up to 4.7 million conflict-affected people, as well as enabling humanitarian organizations to operate in Darfur."
Later this week the UN, its aid partners and the Sudanese Government will launch its joint workplan for 2009 that will include relief and early recovery activities in Darfur.