Russia’s deputy foreign minister brushed back suggestions Saturday that an American being held in Moscow on suspicion of spying could be exchanged for a Russian citizen.

The news that Paul Whelan holds citizenship in multiple other countries adds complexity to an already-murky case.

U.S. ambassador to Russia Jon Huntsman met in Moscow on Wednesday with Paul Whelan, a Michigan man who has been detained on espionage charges as the American government seeks answers about his arrest.