The value of Picasso's work has shot up in the past 30 years

It was stolen by Nazis during World War II from a Paris gallery after being sent there by its Jewish owner.

The painting's current owner, Marilynn Alsdorf, has been ordered not to move it from her Chicago home until a court decides who owns it.

The original owner's grandson, Thomas Bennigson, wants the 1922 oil painting, Woman in White, to be returned.

Ms Alsdorf and her late husband bought the painting from a New York gallery for $357,000 (�195,000) in 1975.

The US government alleges Ms Alsdorf illegally moved the painting from California to Illinois.

Popular attraction

It said the painting was taken into custody because it is against the law to knowingly transport stolen goods across different states.

Mr Bennigson had sued Ms Alsdorf before she transported the painting after being told it had been put up for sale at a Los Angeles gallery.

"The victims of Nazis or their heirs shouldn't have to chase stolen property from one state to another," said Mr Bennigson's lawyer, E Rando Schoenberg.

His case was initially dismissed because it was found that Californian courts did not have jurisdiction over the matter. That decision is now under review.

More scope

Meanwhile, the Picasso Museum in the artist's home city of Malaga has revealed it has attracted nearly half a million visitors since it opened a year ago.

The museum has recently been expanded to include a library and auditorium.

Picasso's grandson, Bernardo Ruiz Picasso, said he was delighted about the plans.

"It's crucial, as it means a better integration of the city's cultural and educational life," he said.

When the museum first opened on 27 October last year, it contained about 90 Picasso works loaned by relatives of the artist and various museums.

The expansion means there will be more than 200 works to see when the new wings open on Wednesday.