The Israeli General Staff launched a large-scale three-day drill on Monday, testing the military's ability to rapidly transition itself from routine activities to an emergency war footing, JPost reported.

In the course of the drill, hundreds of thousands of reservists will receive mock telephone messages asking them to confirm that the call-up system works, and thousands of reservists will be physically called up to bases at short notice.

"This is one of the largest reservist telephone call-ups we've had in an exercise," a senior military source has said. "We want to ensure that the system is well-oiled and working."

The Northern and Southern territorial commands will drill responding to attacks from Syria, Lebanon, and Gaza.

"This is part of of the planned graph of exercises for this year," the source stressed. "It is part of our activities linked to working on our readiness."

During the call up, the Israel Air Force will also place its air bases in emergency mode, and practice rapidly translating intelligence data into air strikes.

The Israel Navy will also take part, testing its infrastructure.

"For the first time, cyber defenses will be a part of a General Staff exercise," the source said.

The Southern Command will seek to apply lessons learned from last summer's Operation Protective Edge, and hold exercises responding to mock rocket attacks from the Gaza Strip.

The Operations Branch will practice coordinating various emergency maneuvers across the country.