Sergei Lavrov, the foreign minister of Russia, announced on Friday that Moscow would soon provide a time for a phone discussion with Antony Blinken, the secretary of state of the United States. Blinken has stated that he wants to negotiate an exchange of inmates imprisoned in Russian and American prisons.

Brittney Griner, a top basketball player for the United States, and Paul Whelan, a former Marine, were both imprisoned in Russia, according to Blinken, who said that Washington had made a “significant offer” to secure their release.

A source said that Washington was willing to exchange convicted arms trafficker Viktor Bout, jailed in the United States, as part of such a deal.

Lavrov told a news conference that talks on prisoner exchanges had been taking place since a summit in Geneva last year between presidents Vladimir Putin and Joe Biden.

He said a time for the call with Blinken was being worked out and he would listen to what his U.S. counterpart had to say.