DUBAI (Reuters) - Heavy and sustained clashes could be heard on Monday in parts of Sudan's capital, residents said, hours before the expiry of a shaky ceasefire deal that had brought some respite from a six-week-old conflict but little humanitarian access.

Fighting continued from Sunday into Monday in the south and west of Omdurman, one of three adjoining cities that make up Sudan's greater capital. Across the River Nile in southern Khartoum residents also reported clashes late on Sunday.

Sudan's army and the paramilitary Rapid Support Forces (RSF) have been locked in a power struggle that erupted into conflict on April 15, killing hundreds and driving nearly 1.4 million people from their homes.

Both sides have said they are considering extending a deal for a week-long ceasefire brokered by Saudi Arabia and the United States that was designed to allow for the distribution of aid and is due to expire at 9.45 p.m. (19:45 GMT) local time on Monday.

Saudi Arabia and the United States said on Sunday that both the army and the RSF had repeatedly violated the truce and had impeded the delivery of humanitarian access and restoration of essential services.

(Reporting by Khalid Abdelaziz; Writing by Aidan Lewis, Editing by William Maclean)