US officials familiar with the situation say that airstrikes against ISIS targets in Syria have been “sharply reduced” since Thursday, when US forces attacked the Syrian military. The move is said to be out of concern that Syria or Russia might retaliate against US warplanes in Syrian airspace.

Russian officials have been very clear that they would respond with military force to future US attacks, but did not appear to be intending to attack the US planes if they go back to just attacking ISIS or other rebel factions.

It’s not clear exactly how much the US has reduced its air presence in Syria in the meantime, however, as only yesterday US forces managed to find time to attack an Internet cafe in northern Syria, and destroy a boatload of civilians trying to flee across the Euphrates River.

Officials would say that the planes active in Syria are only more advanced planes, which would be more likely to survive coming under fire from air defense systems. This is likely to just be temporary, barring any more military actions against the Assad government.