Chess grandmaster Levon Aronian said on Friday he was leaving Armenia and would represent the United States, citing what he said was Armenian officials' indifference to chess as one of the reasons.
The 38-year-old, who is ranked sixth in the world, announced his decision on his Facebook page.
"The past year has been very difficult for all of us with a pandemic, a war and in my case there was personal adversity and the state's absolute indifference towards Armenian chess," he wrote, referring to six weeks of fighting between ethnic Armenian and Azeri forces over the Nagorno-Karabkah enclave.
"I was faced with a choice: quit my job or move to where I am valued," he wrote.
Smbat Lputian, deputy head of the Armenian Chess Federation, said he regretted Aronian's decision.
"This is a big loss for Armenian chess," he told Reuters.
Mike Hoffpauir, president of the US Chess Federation, said it welcomed Aronian's decision to relocate to the United States.
The Saint Louis Chess Club said Aronian was moving to the US city to continue his career and would represent the United States at future competitions.
The International Chess Federation (FIDE) told Reuters it could not comment on Aronian's intentions and plans.
"A player can represent the country/federations where he resides," FIDE said. "That doesn't necessarily imply that he changes his nationality."
Aronian's move follows political unrest in Armenia, where Prime Minister Nikol Pashinyan condemned what he said was an attempted coup on Thursday after the army demanded he quit.