A senior official in Moscow urged the U.S. to consider swapping a jailed Russian pilot convicted of drug smuggling for its own citizens detained in Russia, news services reported.

Konstantin Yaroshenko could be exchanged for "an American or Americans who are imprisoned" in Russia, though the U.S. hasn't responded positively to previous offers, Deputy Foreign Minister Sergei Ryabkov said Monday, according to the Interfax news service. Yaroshenko is serving a 20-year sentence for conspiracy to smuggle cocaine into the U.S. after he was arrested in Liberia in 2010 and extradited to America.

Ryabkov urged the U.S. to make an agreement on swapping Yaroshenko before any verdict is reached in the case of former U.S. Marine Paul Whelan, the state-run Tass news service reported. Whelan was detained by the Federal Security Service in Moscow in December and accused of spying, a charge that carries up to 20 years in prison. He denies the allegation.

The U.S. Embassy in Moscow said on Twitter Monday that Whelan's health has deteriorated in detention in Lefortovo prison, but Russian officials had rejected a request for him to be examined by an external doctor.