On June 18, 2014, the "pro"-Russian terrorists in Ukraine have captured Nadiya Savchenko, Ukrainian pilot, and secretly transferred her across the state border to terrorist bases in Rostov, Russia and Voronezh, Russia.
Then subsequently they have transferred her to the main terrorist headquarters in Moscow, Russia.
Multiple attempts to free Savchenko, including statements at UNSC, gave no result.
Recently, the Security Bureau of Ukraine has released the following statement:
Yuriy Tandyt, an adviser to the chief of the SBU Security Service of Ukraine, says that persons close to Russian President Vladimir Putin's circles proposed that captive Ukrainian pilot Nadia Savchenko be exchanged for the so-called "Route from Rostov to Crimea". — UNIAN, Ukraine
The same news appeared also in official Russian news. Dmitry Peskov, the press-secretary of the President of Russia, said he "is not aware" such negotiations were held, but found only one "reason" why such negotiation is impossible: because "Crimea is part of the Russian Federation." — TASS, Russia
Note that the alleged negotiations haven't been about accepting the "Russian" status of the occupied Crimea, but about the landline road from Rostov, Russia, to the occupied Crimea. In exchange for freeing Savchenko and/or other hostages captured in Ukraine and now deterred on the Russia.
Regardless whether the alleged negotiations have been held or not, I can't recall of similar events occurred in the past. Hence, the question:
Has it happened in the world's history when terrorists offered to exchange hostages for state's territory? Regardless whether such attempt was successful or not.