More than three million Yemenis displaced by civil war are struggling to survive this harsh winter.

The displaced families live in tattered tents in camps outside cities, enduring cold winds, rains and hungry. They fear their malnourished children could face higher risks of death.

In a camp for the internally displaced people on a windy hill outside the Yemeni rebel-held capital Sanaa, around 564 displaced families suffers from worst humanitarian situations.

The displaced families lack clothes, woolen blankets, drinking water, food, medical care, shoes and milk for their children. Many of them sleep hungry on the tent's cold floor until their hands and legs were about to freeze from the severe frost.

"We appeal to any aid organization or charity to visit us," Nabil Salem, a father of six children, told Xinhua in the camp.

"It is very cold, we need blankets, clothes and food," he added.

Salem, his wife and their six children have been in this camp for nearly four years. He was a farmer in a village in the mountainous area of Nehm, near the Yemeni northeastern province of Marib. They left everything behind to escape death after the fighting reached edge of his village in 2016.

Mahdi Mohammed, a father of another displaced family in the camp, also appeals for help.

"We lack the most basic needs such as food, medicine, blankets and education," he said, complaining that his family's tent is very old and rains penetrate it.

Yemen's civil war has been raging on for nearly five years. It erupted after the Iran-allied Houthis stormed the capital Sanaa in late 2014 and forced the Saudi-backed Yemeni government of President Abd-Rabbu Mansour Hadi into exile.

The war has killed tens of thousands of people, mostly civilians, displaced over three millions and pushed the impoverished Arab country into the brink of famine.

The United Nations' Office for Coordination of Humanitarian Affairs in Yemen has estimated 3.3 million people remain displaced, up from 2.2 million last year. It said the number of sites hosting displaced people has increased by almost half over the past 12 months.

The UN Special Envoy Martin Griffiths has been shuttling between the Yemeni rival parties to reach a political settlement for ending the conflict.

The UN humanitarian aid agencies say the conflict in Yemen has caused the world's worst humanitarian crisis in modern history.

The young girls and boys in the displacement camp, about 30 km north of Sanaa, are cold and hungry, but they stare toward the horizon with eyes full of hope.