"The opening bid for the painting titled Maritime Nocturno is 10,000 euros (13,000 dollars) in a closed VIP auction that currently features four participants," said owner of the Darte auctioning house Jaroslav Krajnak.

The mixed-media painting depicts a full moon over a glittering seascape. The top bid had risen to 10,200 euros on Thursday.

"The painting has been offered for sale by an unnamed family of a Slovak painter who probably met Hitler personally when he was struggling to become an artist in Vienna during the early 20th century," Krajnak added.

"I look at him as an artist -- in 1913, when Hitler painted this picture, he didn't know what would become of him in the decades to come."

The auctioning house already sold a painting by Hitler from the same family collection last year for 10,200 euros.