Russian former world chess champion Anatoly Karpov has since March been unable to get a nonimmigrant visa to the United States to teach at a summer camp in New York.

Fellow chess player and friend, Maxim Dlugy, the owner of the Chess Max Academy, invited him.

Karpov, 68, one of the greatest chess players of his time, has visited the United States regularly since 1972, the year that American Bobby Fischer wrested the chess crown from Soviet hegemony.

'He [Karpov] was suddenly called in for an interview in the Moscow embassy and asked, 'Are you going to talk to U.S. senators and congressmen? We'll have to check that out,'' Dlugy told Reuters.

Karpov's visa application is still being processed, staffers for U.S. Representative Carolyn Maloney and U.S. Senator Chuck Schumer said, both of whom contacted the U.S. Embassy in Moscow to inquire about Karpov's status.

'This processing cannot be waived or expedited as it is crucial for the final decision regarding the issuance of a visa,' the embassy's public-liaison unit said in a July 2 letter to Maloney's office.

The embassy said Karpov will be notified "as soon as this process is complete."

Dlugy said Karpov never encountered problems getting a visa during his long career and has taught promising, young chess players at his academy for the past two years.

Federal confidentiality laws prohibit the State Department from disclosing the status of Karpov's application, spokesman Noel Clay said.

Karpov became the 12th world champion in 1975 when, as the top challenger, he occupied the vacated spot after reigning champion Fischer refused to defend his title.

To prove he was the best despite Fischer's forfeiture, Karpov embarked on an active tournament spree winning many while successfully defending his title in 1978 and 1981 before being dethroned by another legend, Garry Kasparov four years later.

Karpov and Kasparov dueled for top chess honors three more times, with Kasparov narrowly defeating him each time.

Karpov still has one of the best tournament records in history, having taken first place more than 160 times.

A native of Zlautost in the Chelyabinsk region, Karpov was inducted to the World Chess Hall of Fame in 2004.

With reporting by Reuters

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