Airstrikes targeting the Libyan capital city of Tripoli over the past week were carried out by Egypt and the United Arab Emirates, according to US officials familiar with the situation.

The officials said the US was "caught by surprised" with the attacks, and had even been given assurances by Egypt that they wouldn't launch such strikes, which targeted the Islamist militias fighting against an ongoing coup attempt by Gen. Khalifa Hifter.

Gen. Hifter had claimed credit for the attacks at the time, saying they were a "joint operation" between him and the international community. It turns out this was indeed the case.

The strikes risk to turn Libya's growing civil war into a proxy war, with Turkey and Qatar backing the militias against the would-be coup general, while Egypt appears to be intent on exporting its own post-Arab Spring coup to its neighbor.