Russia has reopened a historic theater in the occupied Ukrainian city of Mariupol, more than three years after Russian forces pummeled it with an airstrike, killing civilians sheltering inside.

The death toll from the attack on the Mariupol Drama Theater in 2022 is not clear. Human Rights Watch estimates at least 15 were killed, while initial death tolls were far higher, including one by the Associated Press which said about 600 people inside and outside the building were killed.

Hundreds had been sheltering inside the theater and the world "children" had been written in giant letters on the street outside in order to be visible by fighter pilots.

The incident became a symbol of Russia's three-month-long siege of Mariupol in which 90% of the city was destroyed, according to the United Nations, and some 8,000 were killed, according to Human Rights Watch.

Ukrainian authorities condemn 'concealment' of Mariupol atrocities

On Sunday, performers from Russian-occupied Mariupol staged a show in St. Petersburg to mark the reopening of the theater.

"Mariupol Drama Theater has reopened its doors to spectators" after a three year redevelopment, said Denis Pushilin, the pro-Russian leader in the Donetsk region who attended the event.

St. Petersburg Governor Alexander Beglov said the city was a major contributor to the reconstruction of the theater, sending architects and other workers to Mariupol. He called the project "a question of honor."

But the Mariupol municipal authorities that were exiled from the city after the Russian siege called the reopening "singing and dancing on bones."

"The 'restoration' of the theater is a cynical attempt to conceal the traces of a war crime and part of an aggressive policy of Russification of the city. The repertoire consists largely of works by Russian writers and playwrights," the Ukrainian city authorities said in a statement on Telegram.

Russia announced the annexation of Donetsk — as well as the neighboring Ukrainian regions of Luhansk, Kherson and Zaporizhzhia — in 2022, although it does not fully control those areas.

Correction: An earlier version of this story said the Human Rights Watch death toll for the Mariupol Drama Theater attack was 12. This has now been corrected and we apologize for the mistake.

Edited by: Roshni Majumdar