US Secretary of State Antony Blinken said Wednesday he will speak to his Russian counterpart for the first time since the Ukraine war to take up a "substantial proposal" to free detained Americans.
Blinken said he expected a telephone call "in the coming days" with Foreign Minister Sergei Lavrov to push forward an offer to release basketball star Brittney Griner and former Marine Paul Whelan.
The pair "have been wrongfully detained and must be allowed to come home," Blinken told reporters.
"We put a substantial proposal on the table weeks ago to facilitate their release. Our governments have communicated repeatedly and directly on that proposal and I'll use the conversation to follow up personally," he said.
Citing the sensitivity, Blinken declined to go into detail or confirm reports that the United States was offering to trade them for Viktor Bout, a convicted Russian arms smuggler.
The United States and Russia already engaged in one prisoner swap in the heat of the Ukraine war: In April Washington exchanged former US Marine Trevor Reed for convicted drug smuggler Konstantin Yaroshenko.
President Joe Biden's administration has faced growing pressure to free Griner, a basketball star who has pleaded guilty to carrying cannabis oil in Russia. She testified earlier Wednesday at her trial that she did so unintentionally.
Whelan, a security official at an auto parts company, was arrested in Moscow in December 2018 and in 2020 sentenced to 16 years in prison for espionage, which he denies.
Whelan's family in a statement voiced appreciation for the Biden administration's efforts and hoped that Russia "accepts this or some other concession" for his freedom.
- No negotiation on Ukraine -
The telephone conversation will be the first between Blinken and Lavrov since February 15 when the top US diplomat warned Russia against invading Ukraine.
Russia went ahead and attacked its neighbor nine days later, leading the United States and its allies to impose sweeping sanctions and to seek to isolate Moscow on the world stage.
The conversation "will not be a negotiation about Ukraine," Blinken told reporters.
"Any negotiation regarding Ukraine is for its people and people to determine," he said.
Blinken said the United States -- which has been pouring billions in military aid into Ukraine -- was "under no illusion" that Russia was ready to engage "meaningfully and constructively" to end the war.
"In the meantime, we'll continue to do all that we can to strengthen Ukraine's position on the battlefield," he said.
Blinken said he would also urge Russia to fulfill a breakthrough agreement reached last week in Turkey to allow the release of Ukrainian grain after a blockade has sent global food prices soaring.
"Hundreds of millions of people are waiting for these ships to set forth from Ukraine's ports," Blinken said.
He also said he would warn of further consequences if Russia annexes more Ukrainian territory. Moscow in 2014 seized Crimea and declared the peninsula to be part of Russia, a decision not recognized by most of the world.
The White House recently said that Russia was laying the groundwork for "sham referenda" in areas it seized, possibly as early as September.
Lavrov, a veteran diplomat known for his quick, mordant wit, met in person with Blinken on January 21 in Geneva in a last-ditch US bid to warn Russia against invading Ukraine.
With US intelligence determining that President Vladimir Putin was set to go ahead, Blinken on February 22 canceled a follow-up meeting with Lavrov.
Blinken pointedly declined to meet Lavrov when they both attended a ministerial meeting of the Group of 20 economies in Bali earlier this month, with the United States rallying its allies in criticizing Russia in the closed-door sessions.