(CNN) -- Eleven million people are facing a hunger crisis in the Horn of Africa, and they are in desperate need of help.

The United Nations declared a famine Wednesday in parts of southern Somalia, calling for a widespread international response to end the suffering.

Thousands of Somalis have been fleeing the country each week in search of food, water and shelter -- many of them walking for days in the sweltering sun toward refugee camps in Kenya and Ethiopia.

Nearly half a million children are at risk of dying from malnutrition and disease.

Relief organizations are calling on the international community to join together to end the crisis, and they're working to gain entrance into areas with limited humanitarian access.


There are ways you can help.

UNICEF is asking for $31.8 million over the next three months for relief efforts. The money will help provide therapeutic treatment for women and children with severe malnutrition, access to clean drinking water and vaccinations to prevent deadly diseases like measles and polio.

"The earlier we act, the more children we can save. Americans are a generous people, and a little goes a long way -- just $10 can feed a child for 10 days," said Caryl Stern, president of the U.S. Fund for UNICEF.

To help UNICEF's efforts, text "FOOD" to 864233 to donate $10 or visit the website.

International Medical Corps has teams on the ground in Somalia, Ethiopia and Kenya to provide food, water, hygiene, sanitation and mental health services to people in refugee camps.

Visit the website or text "AFRICA" to 80888 to donate $10 to the group's drought relief response. It will show up on your next mobile phone bill.

In central Somalia, the International Rescue Committee is giving cash and other assistance to families whose livestock, pastures and farmland have been decimated and helping to repair boreholes and wells for those left behind.

In overcrowded camps in Kenya, the group has helped establish reception centers for newcomers to receive food, health screenings and medical referrals. In Ethiopia, the organization is bringing in water and installing water-supply systems in three camps serving 82,000 refugees.

Visit the website to make a donation.

The United Nations World Food Programme has plans to airlift high energy biscuits and highly nutritious supplementary foods for children and pregnant or nursing mothers into southern Somalia.

Donations can be made online or via text. To donate $10 from the United States, text "AID" to 27722; to donate $5 from Canada, text "RELIEF" to 45678; to donate £3 from the United Kingdom text "AID" to 70303.

World Vision is working to regain safe humanitarian access in south central Somalia where millions of children are in urgent need of food and assistance.

The organization continues to implement programs in Somaliland and affected areas in Puntland. For families fleeing the drought, World Vision is providing nutrition supplements to malnourished children and improving healthcare and sanitation.

To donate to relief efforts, visit the website or call 1-888-56-CHILD.

Oxfam America is responding to the crisis by providing life-saving water, sanitation services, food and money. The organization aims to reach 3 million people, including 700,000 in Ethiopia, 1.3 million in Kenya, and 500,000 in Somalia.

Visit their website to donate to famine relief efforts.

Staff members from Catholic Relief Services are visiting a refugee camp in Dadaab in eastern Kenya and in surrounding communities that are hosting refugees. Workers are on the ground determining the level of food, water and sanitation needs.

In Ethiopia, the group is leading a Joint Emergency Operational Plan that is feeding more than 400,000 people.

Visit their website or call 1-800-736-3467 to make a donation.

Mercy Corps has teams in Ethiopia, Somalia and Kenya distributing food and water and expanding critical relief efforts. The group is currently on the ground helping more than 150,000 people in the region survive.

Visit the website to make a donation.

ShelterBox, which provides tents and essential supplies to people who have been displaced after disasters, has a response team in Ethiopia and a second team on the way to Kenya.

The teams will be working with the Norwegian Refugee Council and Rotarians to establish how they can be of assistance during the crisis.

To help, visit the website or text "SHELTER" to 20222 for a one-time $10 donation. Location and time specific donations cannot be accepted.

Save the Children has launched a major humanitarian response in Kenya, Somalia and Ethiopia feeding underweight children, providing life-saving medical treatment, and getting clean water to remote communities.

Visit the website or text "SURVIVE" to 20222 to donate $10 from the United States to Save the Children's East Africa Drought and Food Crisis.

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