Former UN secretary general Kofi Annan called Saturday for increased international cooperation to tackle global food security and criticised rich countries for grabbing land from the poor.
"Along with tackling the linked problem of climate change, delivering global food and nutrition security is the challenge of our time," Annan said during a conference held by the UN's food agency in Rome, according to a statement.
Annan, the chairman of the Alliance for a Green Revolution in Africa, said that over the last few years there has been "an ominous retreat from the idea of common purpose based on shared values."
"If countries cannot come together successfully to deliver food security -- this most basic of human needs -- our hopes for wider international cooperation look doomed," he added.
A joint Food and Agriculture Organisation (FAO) and Organisation for Economic Cooperation and Development (OECD) report on Friday forecast that food prices will be high and volatile for the next decade, driven by rising incomes in emerging nations and demand for biofuel.
Global hunger rates have decreased slightly in recent years but 925 million people still suffer from hunger and high food prices threaten millions more.
"We have seen a worrying rise in protectionism, unilateral export bans, land grabs and exclusive deals that meet the food needs of the rich but not the poor," Annan said.
The Nobel Peace Prize winner hit out at the phenomenon of "land grabbing", by which countries buy or lease land in other nations to boost their own food security.
"It is very disturbing that a recent report found that agricultural land that adds up to the size of France was bought in Africa in 2009 alone by hedge funds and other speculators," he said.
"It is neither just nor sustainable for farmland to be stolen from communities in this way, nor for food to be exported when there is hunger on the doorstop," he added.
Annan's comments came on the sidelines of a conference to elect a new FAO head. Brazilian and Spanish candidates are leading the field to take over from Senegal's Jacques Diouf, who is stepping down at the end of the year.