WASHINGTON -- When Russian classical music titans Valery Gergiev and Anna Netrebko take the stage in New York City this month, pro-Ukrainian protesters vow they'll be waiting for them.

The activists are targeting U.S. performances by Gergiev slated to open this week over the conductor's support for Russia's annexation of Crimea, as well as by Netrebko, a world-renowned opera soprano, in response to her public appearance with a Ukrainian separatist leader.

"We want to make sure that when these artists show up in the West, that the public is well aware of what they've been doing," Julia Khodor Beloborodov, founder of a group called Arts Against Aggression, told RFE/RL.

Khodor Beloborodov, 40, says the protests will include picketing and a "surprise" as the Gergiev-led Mariinsky Theater kicks off its two-week residency at the Brooklyn Academy of Music (BAM) on January 14 with a performance of Rodion Shchedrin's The Enchanted Wanderer.

The demonstrations come in response to Gergiev's decision last year to sign an open letter published by Russia's culture ministry expressing "firm" support for the Kremlin's actions in Ukraine.

"We would like to educate people that Gergiev is one of the musicians who signed this famous letter because many people don't know about his position," said Valentina Bardakova, 38, a New York-based elementary school teacher who is helping to organize the protests.

More than 100 people have said on a Facebook page dedicated to the campaign that they will attend the January 14 protest at BAM, and Khodor Beloborodov said organizers are hoping that each performance at the academy will draw a few dozen demonstrators.

"We are planning to be there for all or most of the performances," said the Boston-based Khodor Beloborodov, a native of Kyiv whose family immigrated to the United States in 1990.

A majority of UN members do not recognize Russia's annexation of Crimea in March, while Ukrainian, U.S. and EU officials accuse the Kremlin of supporting separatists fighting in eastern Ukraine -- a charge Moscow denies.

The UN says fighting between Ukrainian forces and pro-Russian separatists has left more than 4,600 dead in eastern Ukraine since the armed conflict erupted there in April.

The Soprano And The Separatist

Activists also plan to demonstrate at performances later this month at the Metropolitan Opera in New York City, where Netrebko is set to star in the Gergiev-conducted Tchaikovsky opera Iolanta.

Netrebko, who supported Putin during his 2012 election campaign, came under fire from critics last month after appearing in public together with Oleg Tsaryov, a leader of pro-Russian separatists fighting in Ukraine.

Photographs of the appearance show Netrebko and Tsarnyov jointly holding up the flag of "Novorossia," a self-proclaimed territory claimed by the separatists.

Netrebko denied the meeting had any political overtones, saying that it was organized only to ensure that her 1-million-ruble donation to the opera house in Donetsk, an eastern Ukrainian city largely controlled by separatists, "would reach its intended destination."

"This donation is not a political act," she said in a statement.

Her comments have done little to placate detractors. Khodor Beloborodov and other activists last month called on the Metropolitan Opera, widely known as "the Met," to "cancel all future performances" by Netrebko.

A response from the Met's customer relations department posted by a member of Art Against Aggression's Facebook page said the company "believes in freedom of expression" and "does not have to be in agreement with the personal views of the artists who perform on its stage."

"We support Ms. Netrebko as one of the world's leading opera singers and we are proud that she sings at the Met," the company said in the response.

Neither the Met nor BAM responded to requests for comment in time for publication.

'Nothing But Admiration'

The planned demonstrations would not be the first politically charged protests to target Gergiev and Netrebko in the United States.

Gay-rights activists disrupted a September 2013 performance of Tchaikovsky's Eugene Onegin at the Met conducted by Gergiev and starring Netrebko after Russia banned the distribution among minors of "propaganda" of "nontraditional" sexual relationships.

Activists gathered outside a Gergiev performance at Carnegie Hall in New York City the following month to protest the law, which has been widely condemned by rights groups and Western officials as discriminatory toward lesbian, gay, bisexual, and transgender (LGBT) individuals.

Less than a month after Russia annexed Crimea, protesters again demonstrated outside a Gergiev performance at Carnegie Hall, chanting "Carnegie hired Putin's puppet" and "Gergiev out of New York," according to The New York Times.

The newspaper noted that "the audience showed nothing but admiration for Mr. Gergiev and his performances, evidently without regard to his politics."