By Magdalena Mis

ROME, July 29 (Thomson Reuters Foundation) - More than 56 million people in 17 countries affected by prolonged conflicts are struggling to feed themselves, trapped in a "vicious" cycle of violence and hunger, two United Nations agencies said on Friday.

Conflict is a leading cause of hunger because it forces people to flee their homes and fields, and disrupts markets leading to higher prices for food.

Farmers are unable to grow their crops or tend to their livestock, a key source of income in many conflict-hit areas.

The U.N. Food and Agriculture Organization (FAO) and World Food Programme (WFP) said there were 17 countries where violence has significantly affected access to food.

They listed them as Syria, Yemen, Lebanon, Iraq, Burundi, Central African Republic, Democratic Republic of Congo, Guinea-Bissau, Ivory Coast, Liberia, Mali, Somalia, South Sudan, Sudan, Haiti, Colombia and Afghanistan.

Here are some facts about the worst-affected populations and the impact of conflict on food security:

-- A hunger crisis affects 14 million people in Yemen; more than half of the population.

-- Nearly 5 million South Sudanese and 8.7 million Syrians urgently need food, nutrition and other assistance.

-- In Central African Republic and Colombia, millions of people are not sure where their next meal will come from.

-- Nearly 90 percent of Syrian refugees in Lebanon need urgent food, nutrition and other assistance.

-- About a fifth of the population in Burundi and Haiti, and 50 percent of the population in Central African Republic face a food crisis.

-- About half of all poor people live in countries affected by conflict and violence.

-- Countries recovering from conflict where people do not have enough food to feed themselves are 40 percent more likely to relapse into conflict within a decade if hunger is not addressed.

Source: The World Food Progamme; The Food and Agriculture Organization (Reporting by Magdalena Mis; Editing by Katie Nguyen.; Please credit Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's rights, corruption and climate change. Visit news.trust.org)