A group of PKK terrorists took 70 passengers hostage late on Friday after blocking the Kars-Erzurum-Iğdır highway in eastern Turkey.They stopped a bus carrying the 70 passengers and held them hostage for two hours. After they released them the terrorists set fire to the bus and three articulated lorries.Turkish security forces have launched an investigation into the terror attack. Gendarmerie units also took extensive measures in the region to ensure road safety.In a separate incident in Çatak town of Turkey's eastern Van province, two suspected PKK militants were killed and one civilian was injured on Friday, sources said.Also, a Turkish soldier was injured in an attack on the Van gendarmerie command on Friday, the sources added.The security operations come after a string of deadly attacks on the country's security forces since the July 20 Suruç bombing in southeastern Turkey, which killed 32 people.Turkey has responded to the bloodshed by also arresting more than 1,300 suspected supporters of groups such as ISIS and PKK.A reconciliation process to end the 30-year conflict between Turkey and the PKK began in 2013, but the process has stalled after the recent murder of a number of police officers and soldiers, which the PKK has claimed responsibility for.