US officials say Russia has rejected a new proposal to secure the release of detained journalist Evan Gershkovich.
The Wall Street Journal reporter was arrested on 29 March and charged with espionage by Russian officials.
Mr Gershkovich, the US, and the Wall Street Journal deny the charges, but he has now spent over 250 days in prison.
On Tuesday, US state department spokesperson Matthew Miller said Moscow rejected a "substantial" offer to free him and fellow US detainee Paul Whelan.
"We have made a number of proposals, including a substantial one in recent weeks," Mr Miller told reporters during a news briefing. "That proposal was rejected by Russia."
He offered no further details on what the US had offered Moscow in exchange for the pair's release.
Mr Gershkovich disappeared after he dropped out of contact with his editors while working in Yekaterinburg, about 1,600km (1,000 miles) east of Moscow, on 28 March.
US officials said Mr Gershkovich's driver had dropped him off at a restaurant and two hours later his phone had been turned off. The newspaper was unable to find him in the city.
Russia's Federal Security Service (FSB) claimed that it had halted him in the process of "illegal activities" and while "acting on US instructions". It further alleged that the journalist had "collected information classified as a state secret" related to the Russian defence industry.
The Wall Street Journal has vociferously denied FSB's claims.
The paper's editor and publisher demanded the journalist's release from prison in a statement released on Monday to mark Mr Gershkovich's 250th day of detention.
"While these moments help us collectively express our support for Evan and to highlight his case, we must also convey our outrage and continue to call for his immediate release," Emma Tucker and Almar Latourwrote wrote. "The passage of time dictates that we work harder than ever to sustain our efforts until Evan is free."
Reporters Without Borders said Mr Gershkovich was covering the Russian mercenary group Wagner in Yekaterinburg, about 1,600km (1,000 miles) east of Moscow.
In the months since his arrest, Mr Gershkovich has been held in Moscow's Lefortovo Prison, a notorious detention center once run by the KGB. Last week a court extended his detention period there until 30 January next year.
Russian officials have previously suggested they are open to a prisoner swap for Mr Gershkovich, but only after a verdict is delivered in his case.
Other Americans - including the basketball star Britney Griner - have been released under similar agreements. Experts say the process in Mr Gershkovich's case could take over a year, however.
Many expected Mr Whelan, a US-Canadian-UK-Irish joint citizen, to be released under the deal that released Ms Griner. A former Marine and corporate executive, he is serving a 16-year sentence for espionage. The US calls his imprisonment politically motivated.
Mr Whelan is being held in Mordovia, an area far south east of Moscow known for harsh conditions in its prison camps.
