PALMYRA WATCH: Islamic State says it won’t destroy Palmyra. Jihadists’ video shows spectacular ancient ruins still intact, though no word on fate of Hebrew inscriptions. It's not clear to me from the content of the article that ISIS have actually said that they won't destroy ancient Palmyra; they have just released that video of the apparently undamaged ruins, which they have also been using as a backdrop for executions.
Background here and links.