ISTANBUL (AP) — Six suspects, including four Russians, have been jailed pending trial over an alleged plot against Chechen dissidents in Turkey, state broadcaster TRT News reported Thursday.

The suspects have been held on charges of “political and military espionage,” the station said. They had been preparing “armed action and spying” against Chechen opposition figures, it added.

The suspects also include one Ukrainian and one Uzbek national.

The report said they were initially detained in the Mediterranean province of Antalya on Oct. 8 in an investigation led by prosecutors in Istanbul. They are being held in Istanbul’s Maltepe prison.

The espionage charge carries a prison sentence of 15 to 20 years.

Many dissidents from across the Middle East and Central Asia have established bases in Turkey and are occasionally targeted. Saudi journalist Jamal Khashoggi was killed in Istanbul in October 2018 in a murder that Western intelligence agencies have said was orchestrated by the government in Riyadh.