Britain will provide additional aid money to South Sudan, where famine has been declared in parts of the country, and to Somalia, where there is a credible risk of famine, the government said on Wednesday.
Britain will provide 100 million pounds ($125 million) to each country in 2017/18 in addition to existing flows of aid.
"The world faces a series of unprecedented humanitarian crises and the real threat of famine in four countries," International Development Secretary Priti Patel said in a statement.
U.N. children's agency UNICEF said on Tuesday that nearly 1.4 million children were at imminent risk of death in famines in South Sudan, Somalia, Nigeria and Yemen.
"These crises are being driven by conflict and drought and we must respond accordingly," said Patel.
The statement said Britain's new support would help bring food assistance to over 500,000 people in South Sudan and up to 1 million in Somalia.