The drone was likely somewhere along that red line. The blue circle indicates where the United States bases its Fifth Fleet. (Source: Google Maps/Max Fisher)

Update: The drone appears to have been even closer than I'd thought. The post is updated to incorporate reporting from the Post's Ernesto Londoño.

Two Iranian jets fired on an unarmed U.S. predator drone over international waters, a Pentagon spokesperson announced on Thursday. The incident, which occurred last week but has just been reported, "raises fresh concerns within the Obama administration about Iranian military aggression in crucial Gulf oil shipping lanes," a CNN report said.

Iran has previously threatened to shut down the nearby Strait or Hormuz, through which 20 percent of the world's oil supply travels.

Above, I've laid a small red line over where the drone might have been. U.S. officials told CNN the drone was over international waters somewhere east of Kuwait; Londoño reports it was 16 miles from Iran's coast. According to international law, Iranian nautical sovereignty extends 12 miles out from its coastline. A smaller blue circle indicates Bahrain, where the U.S. bases its Fifth Fleet, a substantial military presence in the Gulf.

That red line is indeed international airspace, but it's also very close to Iranian soil. This of course doesn't make it okay for Iran to try to shoot the drone down, but it's worth considering how that proximity might be perceived by an Iranian leadership that already feels under siege and threatened by the much more powerful United States.

Last year, a U.S. drone crashed 140 miles within Iran's eastern border.