The US has been in contact with Russian officials to press for the release of Wall Street Journal journalist Evan Gershkovich, White House national security adviser Jake Sullivan said.
It comes as Friday marked the 100th day of the journalist being detained by the Russian government.
Mr Sullivan said he also spoke with Mr Gershkovich’s family representatives and Wall Street Journal officials on Friday about the status of the case and the administration’s efforts to win his release.
The Kremlin earlier this week suggested it is open to a possible prisoner exchange that could involve Mr Gershkovich – but said such talks must be held out of the public eye.
“I do not want to give false hope,” Mr Sullivan told reporters.
“What the Kremlin said earlier this week is correct. There have been discussions. But those discussions have not produced a clear pathway to a resolution and so I cannot stand here today and tell you that we have a clear answer to how we are going to get Evan home.”
The US ambassador to Moscow, Lynne Tracy, was allowed to visit Mr Gershkovich on Monday for the first time since April.
Mr Gershkovich was arrested on spying charges in the city of Yekaterinburg while on a reporting trip.
He is being held at Moscow’s Lefortovo prison, notorious for its harsh conditions.
A Moscow court last week upheld a ruling to keep him in custody until August 30.
Mr Gershkovich and his employer deny the allegations and the US government has declared him to be wrongfully detained.
His arrest rattled journalists in Russia.
Authorities there have not provided any evidence to support the charges.
White House press secretary Karine Jean-Pierre reiterated the US stance that Mr Gershkovich’s detention was baseless.
spy espionage charges for four years.
“Our message to Evan and Paul is this: keep the faith. We won’t stop until you are home,” Ms Jean-Pierre said.
