Syria has admitted that it shot down a Turkish reconnaissance plane because the plane entered its airspace, but insists it was “not an attack.” The incident comes at a time when the Syria regime is intensifying its violent crackdown against dissent. Russia and China — along with Iran — are supporting the regime of Syrian President Bashar Al Assad.

Turkey has threatened to retaliate for the downing of the plane, but did not say what action it would take as it searched for the aircraft’s two missing pilots.

Reports suggest that the Syrians shot down the Turkish Super Phantom jet with the sophisticated self-propelled medium range anti-air Pantsur-1 missile recently supplied by Russia.

The missiles were delivered only recently, and therefore speculation is rife that Russian instructors played a key role in launching them because Syrian military experts would not have had time to master the improved missile system.

The incident has heightened tensions between Turkey and Syria that were close allies before Syria’s 15-month violent rebellion began. It signals that the violence gripping Syria is spilling over the country’s borders.

Turkey is now one of the strongest critics of the Syrian regime. Turkey hosts civilian and military Syrian opposition groups, and helps collect food and other supplies to deliver to comrades on smuggling routes.

Turkish officials say that Syria, which was collaborating with the Turkish authorities in their fight against autonomy-seeking Kurdish rebels, is now turning a blind eye to Syria-based Kurdish fighters who belong to the Kurdistan Workers’ Party. That is only one of the many aspects and fallouts related to the rebellion in Syria,

Beyond the bilateral context, the downing of the plane could be seen as a Syrian message against foreign intervention to end the regime’s crackdown.

Reports have said that the US is considering a limited offensive aimed at weakening the regime’s forces through the imposition of a no-fly zone and strengthening the opposition fighters by supplying heavy weapons. It is already evident that heavy weapons have started to reach Syrian fighters through Turkey.

There is also speculation that the downing of the Turkish plane could have been deliberate. Syria and Russia might have decided that it is time to stop the frequent Turkish air force flights over the Syrian coast for spying on Russian arms deliveries through the Russian naval base in Tartuse.

Whatever the case, the incident is ominous and underlines the negative consequences that the region stands to suffer if the Syrian crisis is allowed to continue.