The U.N.'s children's agency says Zimbabwe is facing its worst malnutrition rates in 15 years due partly to drought caused by the El Nino phenomenon.

UNICEF spokesman Christophe Boulierac told reporters in Geneva that 33,000 children in Zimbabwe — mostly aged 1 to 2 years old — need urgent treatment for "severe acute malnutrition."

Boulierac said Tuesday that the number of hungry families has doubled in the last 8 months, and said UNICEF is appealing for $21 million in support to meet the humanitarian needs in Zimbabwe this year.

Zimbabwe, once known as southern Africa's breadbasket, has increasingly relied on food aid due to persistent drought conditions and a struggling economy. El Nino has caused wetter weather in some areas but drought in parts of eastern Africa like Zimbabwe and Ethiopia.