CAIRO/DUBAI, May 20 (Reuters) - Sudan's warring factions signed an agreement late on Saturday for a seven-day ceasefire as fighting that has plunged the country into chaos and displaced more than a million entered its sixth week.

The ceasefire will take effect at 9:45 p.m. Khartoum time (1945 GMT) on Monday, the sponsors of the talks, the United States and Saudi Arabia, said in a joint statement.

Numerous previous ceasefire agreements were violated. However, this agreement will be enforced by a U.S.-Saudi and international-supported monitoring mechanism, the statement said without providing details.

The agreement also calls for distributing humanitarian assistance, restoring essential services and withdrawing forces from hospitals and essential public facilities.

The fighting between Sudan's army and the paramilitary Rapid Support Forces (RSF) has led to a collapse of order. Stocks of food, cash and essentials are rapidly dwindling, and mass looting has hit banks, embassies, aid warehouses and even churches.

The conflict, which began on April 15, has displaced almost 1.1 million people internally and into neighbouring countries. Some 705 people have been killed and at least 5,287 injured, according to the World Health Organization.

In recent days ground fighting has flared once again in the Darfur region, in the cities of Nyala and Zalenjei.

Both sides blamed each other in statements late on Friday for sparking the fighting in Nyala, one of the country's largest cities, which had for weeks been relatively calm due to a locally brokered truce.