Lawyers acting for the survivors say the companies profited from the work of more than two million slave labourers in the Nazi era.

BBC's Janet Barrie: "Thousands expected to join"

Two separate actions were filed in the US within hours of one another - one against Volkswagen, the second against VW along with its subsidiary Audi and a number of other firms.

Attorney Mel Weiss, acting in the suit against VW, said he was representing Holocaust survivors who were forced to work as slave labourers.

One survivor, Elly Gross, said she was separated from her family at Auschwitz, where her mother and brother died, and taken to work at a VW factory.

She said: "Auschwitz was the hell. The factory where I worked was the skirt of the hell."

Unspecified damages

Mr Weiss said: "The ghost of the Third Reich will hang over every Volkswagen car unless the company takes action and provides justice to the thousands of its former slave labourers around the world."

In the second action, car companies BMW and Daimler-Benz are among those named with electronics giant Siemens, steelmaker Krupp-Hoesch, photography equipment group Leica and weapons manufacturer Diehl.

The damages sought in both cases are unspecified. Lawyers said the amount sought in the suit against the group of companies could reach $150 million, while the suit against VW will seek "hundreds of millions" of dollars.

One lawyer in the second action said they would claim at least $75,000 in damages for each victim and expected thousands of forced labourers to join the legal action.

The second action says all the companies named "contributed to the Holocaust, prolonged it and the war."

Company reaction

One of the first firms to react was the engineering group MAN, which denied that its predecessor GHH used concentration camp inmates as labour during the Nazi era.

A Daimler-Benz spokesman said the company took the issue "very seriously" and had already paid out 20m marks ($11.4m) since the early 1980s to organisations representing Holocaust victims.

VW has announced a plan to establish a voluntary fund to compensate slave labourers who worked at the company's headquarters during the war.

But attorneys acting for the survivors said they thought the fund was insufficient.