Syrian Facebook pages are reporting a series of massive explosions in Damascus, as are the Syrian regime's media outlets. A video claiming to be of these explosions can be seen here:
Given the size of the blasts, and the news that Israeli jets earlier this week struck a shipment of Iranian missles thought to be headed for Hezbollah, everyone is assuming that Israel is behind these strikes as well. Syrian state TV is claiming that Israel hit a "research center," while opposition Facebook pages are saying that several elite units on Mt. Qassioun, overlooking Damascus, were the targets. (Hezbollah's al-Manar TV station is claiming an Israeli jet was shot down, but that seems unlikely.)
Israeli officials are keeping characteristically mum, but it seems plausible that they would have followed up their previous, successful strike with another one aimed at further degrading the Syrian regime's capabilities. Because it's so difficult, not to mention risky, to destroy chemical-weapons stocks from the air, the next-best thing is to take out Assad's means of delivering them. And Mt. Qassioun is reportedly where many of the Syrian regime's best missiles are kept.
If it was indeed Israel, wow, this is awkward for the Syrian opposition. The regime will seek to exploit the raids to tie the rebels to the Zionist entity, after spending two years painting them as an undifferentiated mass of "terrorist gangs." (Syrian television is already testing out this line, according to Reuters: "The new Israeli attack is an attempt to raise the morale of the terrorist groups which have been reeling from strikes by our noble army.")
But the propaganda can cut both ways. The rebels can point to the Israeli attacks as yet more evidence that Assad's army is for attacking Syrians, not defending the country. It's not clear to me which argument will carry the day.
The strikes also promise to hypercharge the debate over Syria in the United States. Advocates of intervention will ask: If Syrian air defenses are so tough, as U.S. officials have been saying, why was Israel able to breach them so easily? Of course, a no-fly zone is a much more difficult and risky endeavor than a one-off raid, but you can expect that important distinction to get blurred.
There's also a message here for Iran, whose nuclear program Israel has vowed to destroy if the Iranians cross Prime Minister Benjamin Netanyahu's red line. Again, taking out Iran's fortified and far-flung nuclear facilities would be vastly more challenging than hitting a few warehouses in nearby Damascus. And U.S. officials doubt that Israel has the capability to do more than temporarily set back Iran's program. But the intended lesson here for Tehran (and Washington) is clear: Israel will defend itself when threatened, and we mean what we say.