MOSCOW (AP) — Russia's deputy foreign minister is brushing back suggestions that an American being held in Moscow on suspicion of spying could be exchanged for a Russian.

Paul Whelan, who also holds Canadian, British and Irish citizenship, was detained in late December. His arrest has led to speculation that Russia could be using him as a pawn to exchange for Maria Butina, the Russian who pleaded guilty last month to acting as a foreign agent in the United States.

But deputy foreign minister Sergei Ryabkov said Saturday that discussing the issue would be premature because Whelan hasn't been formally charged, according to Russian news agencies.

Some Russian news reports earlier had cited unnamed sources as saying Whelan had been indicted on charges that could bring 20 years in prison if convicted.