Security forces arrested a 17-year-old Hamas operative from Gaza, and said they learned many valuable details on Hamas's elaborate network of tunnels across the Gaza Strip.

The Hamas operative crossed into Israel last month, and took part in Hamas's tunnel-digging program, the Shin Bet (Israel Security Agency) announced on Sunday.

In a joint Shin Bet, IDF , and Israel Police operation, the 17-year-old suspect was taken into custody on May 16 after crossing the electronic border fence into Israel.

During a subsequent investigation, the Shin Bet learned that the youth "belonged to the Bet Lahia battalion of Hamas , and that most of his activities belonged to the tunnels," the domestic intelligence agency said.

Details on Hamas's attack tunnels in northern Gaza surfaced during the investigation, the agency added.

Hamas is digging attack tunnels and linking them to its defensive tunnels located in the heart of Gaza. The defensive tunnels are intended for the movement Hamas armed members, out of sight of the Israel Air Force, the Shin Bet said.

The Gazan tunnel network "includes resting rooms that are designed to serve the [elite Hamas ] Nehbe [unit] during emergencies," the Shin Bet said in a statement.

The tunnels contain many entrances, and some have been dug near civilian buildings across the Gaza Strip, including residential buildings, schools, and mosques. This "endangers the civilian population in the Strip," the Shin Bet warned.

The investigation also provided details about how the youth was recruited into Hamas's ranks, the courses and training he underwent, and his activities in Hamas's military wing.

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