BEIRUT, July 24 (Xinhua) -- The families of nine Lebanese servicemen being held hostage by Islamic State (IS) have expressed concerns over the fate of their sons, local LBCI TV reported. Hussein Youssef, the father of captive soldier Mohammed Youssef, said in an interview with LBCI that he was worried about his son, after Hezbollah launched an unprecedented offensive towards the Lebanese-Syrian border region held by the IS-linked al-Nusra Front group. "We have nine servicemen in IS captivity. What is their situation and what is their fate amid this pressure, bombardment and battles?" Youssef asked. He also warned that the families "will not accept that these servicemen turn into a victim" of any military developments. The fate of the nine servicemen has been shrouded with mystery for around two years now and their families have organized numerous street protests to exert pressure on authorities to unveil their fate and secure their release. The nine men were among more than 30 troops and policeman who were abducted by IS during the deadly 2014 battle between the Lebanese army and IS and al-Nusra militants in and around northeastern border town of Arsal. Four of the servicemen were executed by IS and al-Nusra while another died of his wounds. In 2015, al-Nusra released 16 hostages as part of a swap deal with the Lebanese state, however, the fate of the nine others remains unknown.