The United States today announced sanctions against the Russian Federation’s Federal Security Service (FSB) and Iran’s Revolutionary Guards, accusing them of illegally detaining Americans.

The list of new sanctions includes four senior commanders of the Revolutionary Guards’ intelligence service, but at least one of them had already been sanctioned.

Russia’s FSB is also subject to previous US sanctions.

Top Biden administration officials said on condition of anonymity that the new sanctions are aimed at underscoring the consequences for those who attempt to take advantage of the illegal detention of US citizens to exert political pressure or claim concessions from Washington.

There are not a few American prisoners in prisons in Russia and Iran, two countries that have strained relations with the United States.

Last month, the Russian FSB arrested American Wall Street Journal reporter Evan Gershkovich on suspicion of espionage. Former US Marine Paul Whelan, who is serving a 16-year prison sentence in Russia, has been found guilty of espionage.

Washington-Moscow relations are at their worst level in decades after the Russian invasion of Ukraine, but last year the White House and the Kremlin agreed to two prisoner exchanges. The most recent was the exchange of American basketball player Brittney Greiner with Russian arms dealer Viktor Bout.