U.S. Secretary of State Antony Blinken said Wednesday the United States will not rest until Paul Whelan, an American jailed in Russia, is back home safely.
The latest pledge from the government comes as Thursday marks five years since Russian authorities arrested Whelan.
The former U.S. Marine is serving a 16-year sentence on spying charges that he and the United States say are without merit.
"For far too long, Paul and his family have suffered the consequences of the Russian government’s decision to wrongfully detain U.S. citizens," Blinken said in a statement Wednesday.
"Using people as political pawns is unacceptable," he said.
In an interview published by the BBC last week, Whelan said he felt "abandoned" by the United States.
The White House said last week it was working on a new proposal to Russia to free Whelan and Wall Street Journal reporter Evan Gershkovich, who is facing trial on spying charges.
Russia rejected a previous U.S. proposal to free the two Americans that the U.S. considers wrongfully detained.
Some information for this report came from The Associated Press, Agence France-Presse and Reuters.
