Pretty much the biggest escalation possible
Aside from attacking the US directly, this is the most-aggressive thing Iran could do.
These reports aren't 100% confirmed yet but it's getting close. At this point the risk-reward in buying gold and oil is too high to pass up. This could be full-on war by morning.
Update: Reuters is now reporting that rockets have been fired at the Al Asad Airbase, citing an official. There is a lot of fake news out there, but Reuters is as good as it gets.