JERUSALEM (Reuters) -Israel raised its Istanbul travel advisory to the highest level on Monday because of what it said was a threat of Iranian attempts to kill or abduct Israelis vacationing in Turkey. Foreign Minister Yair Lapid said a “huge effort” by Israel’s security forces had saved “Israeli lives in recent weeks”, and thanked the Turkish government for its contribution. He did not give further details. An Israeli security official told Reuters Turkey had arrested several suspected “operatives” of Iran’s Revolutionary Guards. Turkish officials and the Iranian embassy in Ankara did not imm…