Russian officials have asked the U.S. to send imprisoned arms dealer Viktor Bout back to Moscow in exchange for as many as 15 American residents now jailed in Russia, Bout’s wife said Tuesday. The offers have so far been spurned by the U.S., she added.

State Department officials were not immediately available to verify comments made by Alla Bout, who spoke at a new conference at the in New York. But Bout’s wife appeared inside the Russian consulate and was accompanied by Russian officials — an indication that the exchange had official backing from Moscow.

“The Russian government has made attempts at exchange. They offered 14 or 15 people,” Alla Bout was quoted in Tass, the Russian government-backed news service. Bout’s wife said that the Russian offers were “of little interest” to U.S. officials and that the U.S. was intent on Bout serving “his sentence as a warning to others.”

Bout is serving a 25-year sentence at the federal medium-security prison at Marion, Ill. He was convicted in November 2011 on four conspiracy counts stemming from a U.S. Drug Enforcement Agency sting operation. Bout told U.S. informants disguised as South American terrorist operatives that he could provide them with millions of dollars in anti-aircraft missiles and other weapons.

Tass reported that Alla Bout and her daughter are in the U.S. to visit Bout at the prison in Marion. The visits, she said, are scheduled to start September 18 and 19.