Israel has quietly tested ways of defeating an advanced air-defense system that Russia has deployed in the Middle East and that could limit Israel’s ability to strike in Syria or Iran, military and diplomatic sources said.

The sources said a Russian S-300 anti-aircraft system, sold to Cyprus 18 years ago but now located on the Greek island of Crete, had been activated during joint drills between the Greek and Israeli air forces in April-May this year.

The activation allowed Israel’s warplanes to test how the S-300’s lock-on system works, gathering data on its powerful tracking radar and how it might be blinded or bluffed. […]