Ten major aid agencies from the United States and Europe are calling for a "surge" in aid effort to help the nearly 10 million people in Western Africa that are facing starvation.

The groups, which include Oxfam, World Vision, and Christian Aid, say they've been addressing the crisis for nearly six months, but funding has been "paltry and slow."

The most severely affected country is Niger, the world's least developed nation, where seven million people – nearly half the country's population – are without food. Other affected countries in the area, known as the Sahel, include Chad, Mali, Burkina Faso and northern Nigeria.

"In parts of the Sahel, people are scavenging for wild leaves and seeds, and drinking dirty water. Whole villages are starving and desperate for food with children, nursing mothers, and the elderly particularly at risk," said Kirsty Hughes of Oxfam, who notes that delays in responses to a similar food crisis in 2005 cost people's lives.

"In aid ministries around the world, they know this is happening, they know what needs to happen," she says. "The question is: Why don't you act?"

The famine has been brought on by a compound of circumstances including drought, crop failure, pest infestations and increases in food prices.

Delays in funding have resulted in the late purchase and delivery of food to the affected areas.

In Niger, for example, World Food Programme (WFP) distributions began months after the crisis began and with a reduced number of people receiving food aid.

On 2 July WFP announced it will increase the number of people it is helping in Niger from two to 4.5 million after new malnutrition figures were released.

In Chad, where the WFP needs an extra $20 million, food distributions are only planned for only two months while, as in Niger, it will take three or more months for the next harvest to be ready.

"In the Niger countryside, hundreds of farmers and pastoralists - many of them women - are on the move in search of grain, water and whatever grazing land they can find. The children and old people have been left behind in the villages," Christian Aid programme officer Philippe Bassinga, who has been visiting some of Niger's worst affected areas, said.

"Many are facing the same nightmare as their starving and exhausted animals; they no longer have the strength to go in search of help," Bassinga continued. "The question that faces us is this: should we really leave women and children to suffer in silence? Why are we hesitating?"

Other agencies joining the aid effort include ACF/Action Against Hunger, CARE International, Concern Worldwide, Plan, Save the Children, and Tearfund.