After it became clear on Monday that the art works which were stolen in 2005 from the Westfries Museum in Hoorn, the Netherlands, are located in Ukraine, Dutch Foreign Minister Bertt Koenders urged for a rapid return of the Dutch art.

Koenders had contacted his Ukrainian counterpart Pavlo Klimkin and President Petro Poroshenko.

"I have said that we really need their help," Koenders stated to Dutch national broadcaster NOS, saying "I cannot say how likely it is that the art really comes back to the Netherlands, but I think they take it seriously."

Contact with the Ukrainian militia currently possessing the stolen art, as well as diplomatic efforts on the highest levels, so far had no result and therefore the museum and the municipality of Hoorn went for publicity. They fear the collection may be on the brink of being sold to others and concluded the art must be in a deteriorating condition.

On Jan. 9, 2005, 24 paintings and 70 pieces of silverware, the heart of the 17th and 18th century collection, were stolen from the Westfries Museum during a burglary. Last year one of the stolen paintings first appeared on a Ukrainian website.

In July 2015, two individuals reported to the Dutch embassy in Kiev, saying that they represented a Ukrainian volunteer battalion. This OUN militia claimed to have the complete collection of the stolen paintings from the Westfries Museum in their possession.

The militia stated that it was prepared to hand over the paintings to the Netherlands on certain conditions, one of which was that the Ukrainian authorities were not to be involved.

After being informed by the embassy the Dutch police and justice department gave the municipality of Hoorn the opportunity to contact the new owners of the stolen art themselves.

Arthur Brand, a Dutch specialist in art crimes and tracking down stolen art, got the assignment from the municipality to do research and make the contact.

Brand noticed that the present owners had a completely different idea of the value of the stolen paintings. They estimated the value at 50 million euros (54.22 million U.S dollars), while Brand's research showed that the entire collection should be estimated at a minimum of 250,000 euros and a maximum of 1.3 million euros, if in good condition.

Because the collection did not seem well conserved over the last 10 years the current market value should, according to Brand, be no more than 500,000 euros.

Negotiations with the militia therefore failed. According to information Brand received, some of the works from the Westfries Museum were already offered to foreign criminals and Oleh Tyahnybok, leader of the right-wing extremist party Svoboda, and Valentyn Nalyvaichenko, former head of the Ukrainian secret service, might also be involved.

"We have done everything we can and have reached a dead end," museum director Ad Geerdink said in a press release.

"Now that it seems that the art works are disappearing again, we want to sound the alarm to let potential buyers know that they are dealing with stolen art, to give a correct representation of the actual value of the art works, but also to send a signal that these art works only belong in Hoorn," said Geerdink.