The way you react is with total silence - you don't want anyone to know you were vulnerable. And that's also why these types of activities tend not to escalate.
Personally, if countries have to fight I'd prefer they do it quietly like this rather than open war. It's a lot easier to ratchet down the tensions when there has been no rhetoric about the enemy.
And this sort of thing is nothing new, see http://en.wikipedia.org/wiki/Siberian_pipeline_sabotage for example, and there is lots more.
The way you react is with total silence - you don't want anyone to know you were vulnerable. And that's also why these types of activities tend not to escalate.
Personally, if countries have to fight I'd prefer they do it quietly like this rather than open war. It's a lot easier to ratchet down the tensions when there has been no rhetoric about the enemy.
For example: http://en.wikipedia.org/wiki/2007_Israeli_airstrike_in_Syria - mostly silence on both parties part and no increase in hostilities.