The United Nations estimates that at least one million leaders have been detained in a network of detention camps.

On there are widespread allegations of forced sterilization, forced labor and torture occurring in the province.

Mounting international concern has led some multinational companies to cut ties with the region, but Volkswagen has told the BBC that there is so far no evidence that any of their employees have been through the camps.

As our China correspondent, John said.

Worth reports Volkswagen makes more than four million cars a year in China It's many factories here now, a vital part of its global success story.

Except for one open seven years ago in Xinjiang, this plant has found itself in the center of a major controversy, sharing the vast desert landscape with a network of detention camps that China has built in recent years.

Images said to show the mass incarceration of Xinjiang's Wickers and other minorities on their mass transport have helped make this one of the most pressing human rights issues of our time on now, VW is having to defend itself.

We know about the allegation, and it's certainly very much concerns us on.

We took this.

We also serious to check whether any off our supply chains are affected or any off our people are affected.

So far, we haven't found evidence may be absolutely certain that none of your employees in that Xinjiang plant has bean through a campus.

I would say no company could ever make sure the only thing that we do, we apply the procedures.

If you can't be sure.

I mean, shouldn't you just not be there?

Yeah, I'm not sure.

I guess we have a footprint all over the world in different countries where situations are no, not always to a situation how we would like to have it in folks bargain.

But Xinjiang is not just any other place on the reeducation camps and work camps, however much there denied by China raised tough questions for a company founded by the Nazis and one which relied heavily on forced labor during the war.

One prominent German politician describe your company as a company without a conscience complicity in upholding a totalitarian hell in Xinjiang.

With comments like that, Isn't it time to close that plant and leave?

I would say leaving a plant.

It's a serious decision and I guess our history here also in China, has proven that for the benefit off people and society, not only for the benefit off the company, we can mutually developed on whatever the reputational damage from keeping the plant, Volkswagen knows that be a cost to closing it to the anger of a government on which it is now so dependent, John said.

Worth BBC News Beijing.