CAIRO, June 21 (Reuters) - Hezbollah chief Naim Qassem said on Sunday that Israel will not stay in Lebanon, adding that the group would respond to any violation from the Israeli side. His statements came as Israeli officials say that troops are free to act without restriction to eliminate threats in Lebanon despite an agreed ceasefire that took effect on Friday. (Reporting by Menna Alaa El-Din and Ahmed Tolba; Editing by Alexandra Hudson)