The IDF and Shin Bet have exposed three Hamas terror groups in recent weeks behind several terror attacks during and prior to the period of calm, including the kidnapping and murder of Israeli citizen Sasson Nuriel.
The groups were also responsible for the Beer Sheva bombing in August 2005 that left two security men seriously injured.
The arrests were cleared for publication Monday.
According to the Shin Bet, the cell responsible for the murder of Nuriel was instructed by Hamas headquarters in Gaza to kidnap an IDF officer who had been involved in the drug trade.
In order to improve the cell's operational capacities, the Gaza commanders sent an explosives expert to train the men in the West Bank.
The expert, a 22 year-old woman by the name of Samer Sabih joined the group in the West Bank town of Tul Karem and taught them how to prepare explosive devices.
Additional kidnapppings planned
In September, two cell members who worked with Nuriel forced him to join them for a ride to Aram in northern Jerusalem in order to buy coffee.
While on their way, the terrorists kidnapped Nuriel at gun point and took him into hiding where he was compelled to recite a statement in support of Hamas, while being filmed by his abductors.
Fearing exposure by the IDF, the members attempted to keep Nuriel alive. However, the terrorists later took Nuriel to a garbage dump near Bitunia where they stabbed him to death and buried his body.
A senior Shin Bet official said Nuriel was murdered even before his family was able to filed a missing report with the police.
The cell members reported the murder to their commander in the Strip, and relayed to him photos of Nuriel.
Only after the Shin Bet exposed the operation and uncovered the body, did Hamas claim responsibility for the murder.
According to the Shin Bet, the cell members plotted to carry out further terror attacks, including kidnapping Jews in various areas of Jerusalem and carrying out a suicide bombing at an army base.
However, their plans were thwarted due to their arrest.
Plans to kidnap soldiers' bodies
The IDF and the Shin Bet further revealed that another one of the cells exposed was planning to carry out a terror attack in an IAF base in the Judea desert, by using a massive explosive device.
Additional attacks that have been thwarted include plans to fire at an army jeep and kidnap the bodies of the soldiers riding it, as well as plans to kidnap hikers in the Judea desert area.
The security forces also exposed the Hamas military infrastructure in Dahariya, which has been operative since 2002.
The Dahariya cell was behind several terror attacks near Hebron and in the southern Negev region, which resulted in the deaths of four Israelis and injured dozens.
Hamas continues with terror
A source in the security administration said Monday that "the chain of terror attacks and attempted attacks has continued throughout recent months, despite Hamas' declarations that it accepts the terms of the state of calm."
"However, Hamas refrained from claiming responsibility for the terror attacks carried out recently, probably wishing to 'enjoy the best of both world': A continuation of the attacks, restraint on the Israeli side, and avoiding the political consequences in the Palestinian street," the source said.
A Shin Bet senior official said Monday that "in the wake of the disengagement, Hamas is showing clear signs that it is shifting terror activity to the West Bank."
"The investigation revealed that Hamas headquarters was involved with anything pertaining to military operations," he said.
Islamic Jihad a more imminent threat
The official added that the Shin Bet has seen no signs that the Palestinians are willing to confront the terror organizations.
"However, in recent months, and particularly in recent weeks there has been an improvement. If the PA receives a concrete warning about a terror attack, it moves in against it," the official said.
"In the strategic level, the threat to Israel from Hamas is greater, but in the immediate level – the Islamic Jihad poses a more imminent threat. This is because Hamas is active in the political arena, while the Islamic Jihad is merely a terror organization," he concluded.