The United Nations has warned that extreme winter weather has killed more than a million livestock in Mongolia.

The organisation said this was likely to harm the country's food supply and worsen poverty.

It said 19 of Mongolia's 21 provinces had been hit by heavy winter snow and -40C temperatures.

Mongolia suffered a severe drought during the summer months, which prevented the stockpiling of food for livestock.

More than a third of Mongolians herd livestock for a living in the poor, landlocked country.

"The poor did not have the resources to stockpile food or fuel for heating, and the supplies in the now inaccessible villages as a whole are stretched," said Rana Flowers, the UN's resident coordinator in Mongolia.

Ms Flowers said UN agencies were trying to reach the worst-hit people, and are particularly concerned about pregnant women cut off from medical facilities by the heavy snow - three have reportedly died in childbirth so far, she said.

The agencies are also worried about pneumonia rates among children and pregnant women, and increasing malnutrition.

The UN is coordinating all donor contributions to Mongolia, after the government asked for food, medicine, heating supplies, warm clothing and money to buy and deliver food for livestock.