Authorities in Russia’s second city St.

Petersburg removed a piece of public art celebrating the city’s friendship with its twin city Mariupol from the city’s main square overnight on Thursday, a month after it was vandalized by a local teenager.The installation, entitled “Twin Hearts,” was made up of two intertwined hearts depicting the “brotherhood” of Russia’s northern capital with its largely flattened Russian-occupied twin city of Mariupol in southern Ukraine.The festive display was installed on Palace Square outside the Hermitage Museum on Dec.

13 but had to be taken away for restoration within days after a local high school student allegedly wrote on it:  “Murderers, you bombed it to rubble.

Judases”. The installation was returned to public display on Dec.

20, since when it has been kept under 24-hour surveillance.

A 17-year-old has been charged with “discrediting” the Russian army for his alleged act of vandalism. After weeks of fierce fighting and a three-month seige Mariupol finally fell to the Russian army in May following the surrender of the last Ukrainian fighters at the city’s Azovstal steelworks.

Most of the buildings in the city were reduced to rubble during the fighting. Following Mariupol’s fall, St.

Petersburg Governor Alexander Beglov signed an agreement with Mariupol's Moscow-installed mayor Konstantin Ivashchenko to twin the two cities.

It later became known that St Petersburg donated $1.5 million of its own budget funds to fund Mariupol's rebuilding efforts.