Secretary of State Antony Blinken spoke with Russian Foreign Minister Sergey Lavrov, the State Department said Sunday, calling for the release of Evan Gershkovich, the Wall Street Journal reporter who was arrested in Russia on Thursday on espionage charges.

Blinken “conveyed the United States’ grave concern over Russia’s unacceptable detention of a U.S. citizen journalist,” and called for Gershkovich’s immediate release, State Department spokesperson Vedant Patel said in a statement.

The call between Blinken and Lavrov marks a rare communication between high-level U.S. and Russian officials amid tension over Russia’s war in Ukraine. Gershkovich’s detention is the most high-profile arrest of a U.S. citizen since the war began, though WNBA star Brittney Griner was arrested days before Russia launched its invasion. She has since been released.