The U.S. Embassy in Moscow has hung a rainbow flag on its front facade, photos posted on social media Thursday show.

Starting Thursday, Russians will vote on a set of constitutional amendments that would add language defining marriage as a union between a man and a woman to Russia’s basic law. The provision has been criticized by Russian LGBT activists, who say it would effectively prevent gay marriage from ever being legalized.

“LGBTI rights are human rights. Human rights are universal,” the embassy wrote on its Instagram. “Everyone deserves to live free from hatred, prejudice and persecution.”

Thursday also marks the 42nd anniversary of the rainbow flag’s first appearance as a gay pride symbol at the 1978 Pride parade in San Francisco. 

Displays of the rainbow flag are uncommon in Russia, where the display of “homosexual propaganda toward minors” is outlawed and intolerant attitudes toward the LGBT community persist. The U.S. has long been critical of Russia’s gay rights record.

President Vladimir Putin’s spokesman Dmitry Peskov told reporters that Kremlin staff hadn’t noticed the flag at the U.S. embassy, but added that “in any event, any display of propaganda of non-traditional sexual minorities in our country is not allowed by law.”

Earlier this month, U.S. President Donald Trump banned the country’s embassies from flying the rainbow flag during June, which is celebrated as LGBT Pride month around the world. Because the ban only applies to official flagpoles, embassies have placed the flag inside their buildings and hung it on exterior walls as workarounds.