The United States and Saudi Arabia have called on Sudan's warring parties to extend a ceasefire that expires tomorrow.

The Sudanese army and rebel forces, which have been fighting for control of Sudan since mid-April, agreed to a week-long ceasefire brokered by the US and the Saudis last week.

However, this ceasefire, like those before it, did not stop the fighting in the capital Khartoum and across the country.

In a joint statement today, the United States and Saudi Arabia called for the extension of the ceasefire, which expires Monday at 21:45 p.m. local time.

"Although the ceasefire is not complete, its extension will facilitate the delivery of urgently needed humanitarian aid to the Sudanese people," the statement said.

It calls on both Sudan's military government and rival forces to support the continuation of negotiations to extend the ceasefire.