A Hamas security official said that the five were arrested during overnight crackdowns, the Associated Press reported.
The unnamed Hamas official went on to warn of a tough stance in dealing with those detained, saying, "We are not going to show any mercy to those involved in spying on our people.''
The suspects were arrested after they missed a two-months-long deadline to turn themselves in.
The issue of Israel spying on Palestinians is nothing new. An Israeli espionage network is functional in the occupied West Bank, taking orders from the security service Shin Bet.
Israel placed Gaza under an all-out siege in mid-June 2007, reacting to Hamas' accession to power, claiming that the siege was aimed at preventing alleged security hazards to the region by the movement.
In late 2008, Israel launched a war on Gaza, killing more than 1,400 Palestinians." (source)
