Is there a term describing countries taking foreign citizens as hostage?

English is my second language, and I am wondering is there a term that describes when countries take foreign citizens or dual citizens as hostage or arrest them on conspiracy/espionage charges all to pressure their government?

The reason I am asking this is I feel like it is getting pretty common approach with dictatorship governments and I thought maybe there is a term for it.

Some of the examples include:

• British citizen prisoned in Iran
• U.S. citizen prisoned in Turkey
• Australian citizen detained in Iran
• French resident prisoned and executed in Iran