One week after Turkey shot down a Syrian warplane near the border, tensions continue to grow, and Syria has announced the deployment of anti-aircraft missile batteries along the border to repel “hostile” Turkish planes.

It’s a possibility that seems more likely by the day, after a leak last week revealed the Erdogan government talking about using the security at an Ottoman-era shrine as a pretext for invading northern Syria outright.

Today saw even more acrimony, as Turkey reported mortar shells landing on their side of the border from the civil war, and launching artillery attacks into Syrian territory.

Syria’s information ministry also accused Turkey of orchestrating some of the rebel attacks in Latakia Province, saying they’d sent foreign fighters “armed to the teeth” into Latakia to join the fight against the Assad government.

Turkey and Syria were once close allies, but early in the civil war the Turkish government began openly backing the rebels.