ISTANBUL, Turkey, July 26 (UPI) -- A cyberattack on two Turkish airports delayed flights and left travelers waiting in line for hours Friday, officials said.

The attack knocked out passport control systems at the Ataturk and Sabiha Gokcen international airports in Istanbul, the Dogan News Agency reported.


Security officials said the airports' Polnet data system was disabled.

Lines at passport control points grew dramatically as passengers were unable to board their flights.

The system was eventually restored, but many departures were delayed for hours at Ataturk.