MADRID (AFP) - Thieves in Spain stole a truck containing about 20 works of art, including at least one by Pablo Picasso, worth at least five million euros (6.6 million dollars), officials and reports said Thursday. The works were to be delivered to galleries in Madrid and Barcelona after being on display at an exhibition in Germany, reports said. Three masked men stole the parked truck on Saturday in an industrial zone in Getafe on Madrids southern outskirts, Getafe town councillor Sara Hernandez told a news conference. The way it was carried out leads us to believe that there was inside information that facilitated the theft of this truck because they had plenty of information regarding when it arrived, when it would leave to distribute art to other cities and galleries, where the truck was, she said. A police spokesman refused to confirm the details of the theft, saying only that an investigation was underway. Hernandez and police would not say exactly what art was stolen. But the online edition of the daily newspaper El Pais and other media said the haul included at least one drawing by Picasso as well as works by Colombian artist Fernando Botero, Spanish sculptor Eduardo Chillida and Catalan artist Antoni Tapies. Many of the stolen works were not insured, said David Fernandez Braso, the owner of the Juan Gris gallery which was due to receive a shipment of art from the stolen truck. I am very concerned, upset and angry, he told Telemadrid television. In our gallery, in my 40 years of experience, nothing like this has ever happened. But during this really tough time, many galleries do not insure their works, which is awful. The Crisostomo transport company responsible for the truck said in its police complaint that the keys to the vehicle were in the glove compartment at the time of the theft, he added. The truck was found on Tuesday without the artwork. Police have questioned the driver of the truck, a Romanian national, daily newspaper ABC reported. Police estimate that only 15 percent of stolen art is ever recovered.