Back in May, a suicide bomber struck a Shi'ite mosque in eastern Saudi Arabia during prayers, killing more than 20 people. The blast was claimed by ISIS, and as we said afterwards, "we're no weathermen, but based on recent history in Yemen we wonder if a 'Decisive Storm' might be on the horizon in Syria.’” Fast forward to Wednesday, and Turkey’s foreign minister Mevlut Cavusoglu was busy talking up a new "comprehensive battle plan" which Ankara is purportedly set to launch with the help of the US military. The target: why ISIS of course, and as we noted yesterday, no one should be at all surprised that Cavusoglu also mentioned the distinct possibility that Saudi Arabia and Qatar will join the fight as part of an anti-terror "coalition." Of course this is all simply a smokescreen on the way to removing Bashar al-Assad from Damascus, and just in case Saudi Arabia - which is also fighting another proxy war in Yemen - needed a new excuse to invade Syria it got one on Thursday when tragically, another suicide bomber struck, killing 13 at a mosque inside a state security unit. Here’s Reuters: A suicide bomb attack inside a mosque in a local security forces headquarters in Abha city in south-west Saudi Arabia killed 13 people and wounded nine on Thursday, the Saudi state news agency reported, citing an interior ministry spokesman. State television had earlier reported a death toll of 17. The mosque in Abha, the capital of Asir province, was part of the local headquarters of a state security unit called the Special Emergency Force, the spokesman was cited as saying. Of those killed, 10 were members of the force, while three were workers in the compound. They were praying when the bomber struck within their ranks, he said. And here's BBC: A senior Saudi official told the BBC the bombing targeted a mosque used by security forces in Abha, close to the Yemeni border. Two deadly attacks on Shia mosques in May were claimed by the Islamic State (IS) group. Saudi Arabia is also heading a campaign against Shia-led rebels in neighbouring Yemen. Saudi TV reports that many of those killed were members of the security forces. The mosque was used by a Swat team tasked with domestic security, officials say. It is not yet clear who carried out the attack and no group has yet claimed it. Last month Saudi authorities arrested 431 suspected members of IS, accusing them of plotting suicide attacks on security forces and mosques in various parts of the country. Obviously this took place closer to Yemen than to Syria, but we suspect it will be promptly blamed on ISIS, and regardless of who ends up taking "credit" for the attack, it will almost certainly be trotted out as evidence for why the Kingdom needs to get more aggressive when it comes to countering terror threats both to the north and the south.