It is now being more publicly stated that Israel struck a partly constructed nuclear reactor in Syria last month. Note this paragraph:

"A senior Israeli official, while declining to speak about the specific nature of the target, said the strike was intended to “re-establish the credibility of our deterrent power,” signaling that Israel meant to send a message to the Syrians that even the potential for a nuclear weapons program would not be permitted. But several American officials said the strike may also have been intended by Israel as a signal to Iran and its nuclear aspirations. Neither Iran nor any Arab government except for Syria has criticized the Israeli raid, suggesting that Israel is not the only country that would be disturbed by a nuclear Syria. North Korea did issue a protest."