LONDON (AlertNet) - Britain's leading international aid charities have joined forces to launch an emergency appeal for more resources to deal with the growing humanitarian crisis in Darfur and neighbouring countries.

The British Red Cross, Oxfam and Save the Children are among the charities taking part in the Darfur and Chad Crisis Appeal as the rainy season threatens to exacerbate conditions for people in Darfur, Chad and the Central African Republic.

Humanitarian agencies say they need to bolster their stocks of food and medicine before the downpours - which could hit any time in the next month - wash away road tracks and flood rivers, making it more difficult to deliver aid.

Life-threatening conditions like diarrhoea and malaria are also a growing threat, especially for children and the elderly.

"We are seeing one of the greatest concentrations of human suffering right now in Darfur and Chad and the impending rains will make the situation even worse," said Brendan Gormley, chief executive of NGO umbrella group Disasters Emergency Committee (DEC).

"We have been keeping people alive, but access is already severely hampered by conflict and the rains will make it much harder for us to respond if we don't act now. The fact that the UK's leading agencies have come together to appeal shows the severity of the situation."

Four million people in Darfur - two-thirds of its population - have become dependent on aid since the crisis began in 2003, according to the DEC. More than 2 million people have been displaced, fleeing to camps within the country or to Chad.

The DEC estimates that, with the crisis escalating in the first part of this year, 4.5 million people are now affected by the conflict.