A new exhibit that includes German art looted by Russian soldiers after the Second World War is casting a shadow over Chancellor Angela Merkel's official visit to St. Petersburg to meet with President Vladimir Putin.

Merkel had been scheduled to speak Friday evening at the opening of the new exhibition The Bronze Age of Europe: Europe Without Borders at the city's famed Hermitage museum.

The show includes some of the German artworks Soviet soldiers snatched as trophies from Germany, with the museum displaying some items for the first time in decades.

Merkel had been expected to reference the plundered pieces and call for their return. However, the speaking engagement has been nixed, with officials cancelling opening remarks by both Merkel and Putin, citing lack of time.

The pair nonetheless visited the exhibition, where Merkel noted pointedly that some of the items on display had been brought from Germany and "it gives us great happiness that we can see all of them today.   "We will continue dialogue on all questions regarding valuables brought from Germany," she added, according to the news agency Interfax.

The decision to cancel the speech sparked an uproar amid Germany media outlets, which have described it as further indication of deteriorating relations between the two countries.

Merkel is with Putin in Russia for an economic forum in St. Petersburg.

With files from The Associated Press and Reuters