The African Union says a donors conference in Addis Ababa Thursday raised more than $350 million in cash for Horn of Africa drought relief.

AU Commission Chairman Jean Ping told reporters the donations included $300 million from the African Development Bank and $51 million from other African sources and nations.

The AU has been criticized for its slow response to the drought and famine crisis, which has forced hundreds of thousands of Somalis to flee their homes in search of food and water.

Before Thursday, the 54-member bloc had pledged only $500,000 in aid.

The donors conference had been scheduled for earlier this month, but the AU postponed it, citing conflicting schedules.

Four heads of state attended the one-day conference, including the leaders of three countries affected by the drought — Somalia, Djibouti and Ethiopia.

U.N. Deputy Secretary-General Asha-Rose Migiro told the conference the AU must be at the forefront of the response to the crisis.

The United Nations estimates that some 12 million people across the Horn of Africa are in need of food aid.

The U.N. recently declared a famine in five regions of southern Somalia and predicts famine conditions will spread throughout the entire south of the country by the end of next month.

The world body has said $2.5 billion is needed for drought and famine relief.

The United States has pledged more than $500 million in food aid and refugee assistance. The European Union and its member countries have pledged more than $750 million, while the Organization of the Islamic Conference pledged $350 million.