Israeli troops are still determining the full extent of a tunnel running into Israel from the southern Gaza Strip, which was discovered earlier this week, the Israel Defense Forces announced Friday.

The tunnel, which extends several hundred meters into Israel territory, is among the largest and most sophisticated ever found, the army said. It is the fourth such tunnel discovered in the past year-and-a-half.

For most of its length, the tunnel is at a depth of between eight and nine meters, though it runs as deep as 20 meters in some places.

Among the equipment found in the vicinity of the tunnel were generators, security kit and concrete reinforcing. The IDF estimates that the tunnel was built over several months and was worked on until recently.

"It's a very high-quality tunnel and much thought went into it," a senior IDF source said. "This sort of tunnel is built for a large operation – a kidnapping or something similar." A tunnel was used in the kidnapping of Gilad Shalit in June 2006.

The source added that the IDF's Gaza Brigade has ramped up its tunnel prevention activities recently, including the deployment of special teams for that purpose.

In a special press conference in Gaza on Thursday, the military wing of Hamas, Iz al-Din al-Qassam, said that the tunnel was not new, and had been unearthed months ago when rainfall caused its collapse.

"The occupation is hysterical and confused in the face of the resistance army's tunnels, but we're ready for any scenario and we'll teach the enemy a harsh lesson," the group's spokesman, Abu Obeida, said.

"Despite the psychological warfare used by our enemy against the Palestinian people, the Palestinian opposition will have the upper hand," he added, and warned that "Israel must not rejoice to quickly for its supposed security achievements because the repercussions of its actions against our people, prisoners and land will be severe and will exact a heavy toll."

In response, the IDF said that Hamas "is under tremendous pressure. The discovery of the tunnel is a huge blow to them."

Last October, Israeli soldiers discovered a tunnel on the Gaza border, which according to security forces, was going to be used by Palestinian militants to enter Israel and launch attack soldiers or civilians. The forces located multiple entry points to the tunnel within Israeli territory, near Kibbutz Ein Hashlosha and spent several days destroying the passageway.

The tunnel stretched an unusually long 1,800 meters, 300 meters of which were beyond the Israeli border. Officials added that the though the tunnel had not yet been used, but it was designed as infrastructure for terrorists to use in the future.

In January of last year, a previous tunnel was revealed near Kibbutz Nir Oz. The incident was considered unusual at the time, only a few months after the Pillar of Defense Operation, but security sources estimated that the tunnel was not new, but rather old infrastructure dating back to before the operation unearthed by rainfall.

Several days before the operation was launched a booby-trapped tunnel was found near Kibbutz Nirim.

All three tunnels were discovered opposite the city of Khan Younis, in the south central area of the Gaza Strip. In the past, a military source said that a "double-digit" number of similar tunnels are in existence.



Open gallery view Inside the tunnel, March 20, 2014. Credit: IDF Spokesman