Battles are reportedly ongoing in the Syrian capital city of Damascus after a sudden attack by ISIS fighters has left them with possession of part of the Qadam District, the first time any rebel faction has had anything meaningful inside the capital itself.

Actually how much is held in the city is unclear, with the Syrian Observatory for Human Rights claiming that ISIS only holds a couple of streets, but ISIS themselves saying they hold half of the very significant district, and showing video of their fighters advancing significantly.

ISIS’ main target in the area near Damascus has long been the Palestinian refugee camp of Yarmouk, which had been a de facto suburb of the capital before the war. Now, the fighters are pushing into the city itself, something that was once seen as unthinkable.

Attacks inside Damascus during the civil war have previously centered on hit-and-run strikes or bombings in important neighborhoods, with the Syrian military so heavily shoring up the defense of the city even as it loses more of the country.

In recent weeks, however, there’s been talk that the Syrian military is just plain on its heels nationwide, and that appears to have convinced ISIS, which has been previously taking the country’s central region, that the capital is no longer completely unthinkable to target.

This also raises the possibility that a rapid collapse of the Assad government to ISIS, considered a “worst-case” scenario

by the international community, if they don’t have any place that is so defensible that it can’t possibly fall to a sustained offensive.