GENEVA (Reuters) - A United Nations human rights panel said on Wednesday it had credible allegations that North Korean authorities had tortured or mistreated children forced to return from abroad or held in detention.

A North Korean flag flies on a mast at the Permanent Mission of North Korea in Geneva October 2, 2014. REUTERS/Denis Balibouse/File Photo

It also called on Pyongyang to halt child labor in farming, mining and construction, as well as discrimination against youth for the “crimes” of their parents.

The U.N. Committee on the Rights of the Child, which reviewed Pyongyang’s record last month, voiced deep concern at what it called the “ideological indoctrination” in its education system and malnutrition among North Korean children.

“We do have reports which are credible that children are at least to a certain extent tortured or exposed to violent treatment by the authorities in various circumstances,” panel member Kirsten Sandberg told a news briefing.

“This might be when they return to the country after having tried to stay abroad and then are being forcibly returned. It happens on the border, we’ve heard reports about violent treatment,” she said.

This involved mainly North Korean children returning from China, Sandberg said, adding: “We also have reports of pregnant mothers coming back or being forcibly returned who are not to allowed to keep their babies.”

“We also have reports of violence against children in detention,” she said.

Tensions in the region and beyond, especially with the United States, have risen considerably in recent months as North Korea conducted a series of tests of its medium- and long-range ballistic missiles, some of which flew over Japan, as well as its sixth nuclear test on Sept. 3.

The U.N. panel, in a session on Sept. 21, asked the North Korean delegation how “songbun”, a system ranking citizens based on family loyalty to the ruling dynasty, affected children’s access to education, health and food.

The North Korean delegation replied that this was an “imaginary concept” invented by hostile forces.

In its findings, the U.N. panel said it had “reports of discrimination against students based on their social status and political views of their parents”.

CHILD LABOR

North Korea has a “serious nutrition problem”, Sandberg said. “There is still an over 40 percent rate of under-nourishment. This also a serious underlying cause for child mortality, also mortality of their mothers.

“And children under five years continue to suffer from high rates of stunting and wasting,” she said.

Children are told to “volunteer extensive periods of their day to work on farms and mines, collect wood in the forests, repair railroads, clean statues and participate in forestation initiatives and construction projects,” the U.N. panel said, noting these were referred to as “economic assignments”.

The watchdog, composed of 18 independent experts, also called on North Korea to allow children freedom of expression, including access to the Internet.

North Korea told the U.N. panel last month that international sanctions imposed on it over its nuclear and ballistic missile programs would endanger the survival of North Korean children.

There was no immediate reaction from Pyongyang to the findings, but a North Korean diplomat in Geneva told Reuters just before they were released: “We are committed to dialogue”.