Secretary of State Hillary Clinton said more than two million Somalis still need urgent assistance despite the end of a famine earlier this year, while the region faces crises fueled by conflict, floods or drought.

"The United States continues to be concerned by the crisis in the Horn of Africa," she said, adding: "The overall humanitarian situation in the region remains fragile; more than nine million people in the Horn need assistance."

In 2011, famine in Somalia caused the deaths of tens of thousands of people and affected more than four million people, or more than half of the population, according to UN figures.

Washington is "proud" to be the largest humanitarian donor to the region, having given over $1.3 billion since 2011 in emergency aid for Somalia, Kenya, Ethiopia, and Djibouti, Clinton said in a statement.

The US "is also fighting chronic food insecurity by helping vulnerable communities diversify and adapt their livelihoods, improve smallholder agricultural and other efforts so they can become more resilient," she said.

"We will keep working with our partners and targeting those most in need until every man, woman and child has the chance to live healthy lives and realize their potential," added Clinton.