Warning to troops
The Lebanese army warned its troops against Israeli attempts to infiltrate the military.
Saturday's warning came days after security officials said authorities detained a Lebanese army colonel on suspicion of spying for Israel in the first case involving a high-ranking military officer.
Since the hunt for spies began in April, Lebanon has arrested 35 people on suspicion of spying for Israel, Brigadier General Ashraf Rifi, a Lebanese police commander, told the Associated Press news agency.
Lebanon considers itself at war with Israel and bans its citizens from having any contact with the country.
Spying for or collaborating with Israel can be punishable by death.
Some of the 23 people who have been charged are still at large.
Those in custody have all been accused of providing intelligence to Israel on the Lebanese group Hezbollah, which fought a 34-day war with Israel in 2006 that killed 1,200 people in Lebanon and 159 in Israel.