FACTBOX: The Gaza-Egypt border corridor
(Reuters) - Israeli military plans in the Gaza Strip include the option of retaking the narrow stretch of land that separates the coastal enclave from Egypt.
The move could help Israel destroy the remaining tunnels beneath the so-called Philadelphi corridor to prevent Hamas from rearming. It could also increase pressure on international powers and Egypt in talks over a ceasefire.
Israel wants any truce to include guarantees Hamas will be prevented from bringing in more rockets. But reoccupying the corridor could also prove risky to Israeli troops.
WHAT IS THE PHILADELPHI CORRIDOR?
The 14.5-km-long (9 mile) sandy corridor has long been criss-crossed by a network of tunnels which allowed Palestinians in the coastal enclave to smuggle in weapons and commercial goods, circumventing an Israeli-led blockade.
The name Philadelphi was randomly chosen by the Israeli army as a code name for the border zone, which divides the town of Rafah into two, one Palestinian, one Egyptian.
European monitors were stationed at Gaza's only border crossing with Egypt, at Rafah, until Hamas Islamists seized control of the coastal enclave in June 2007 from forces loyal to President Mahmoud Abbas, leader of the Palestinian Authority.
Israel's current offensive in the Gaza Strip has included air force sorties in which "bunker buster" bombs were dropped along the Philadelphi corridor, exploding underground and sending out shockwaves designed to collapse the secret passages. It is unclear how many have been destroyed.
HOW MANY TUNNELS ARE THERE?
Before the offensive, Israel estimated there were hundreds of smuggling tunnels. Palestinians say the number topped 3,000. The tunnels include deep passages wide enough to bring through items as large as farm animals and Katyusha rockets. Leading to these are a matrix of smaller access shafts.
Israel dropped leaflets urging many Rafah residents to leave their homes next to the corridor. Israel destroyed some of these structures, asserting they contained entry shafts. Analysts said Israel's aim may be to widen the buffer zone between Gaza and Egypt to accommodate troops or border fortifications.
BORDER FORTIFICATIONS
One ambitious option, Israeli officials said, was to build an underground wall, but doing so would take many months and it was unclear whether Cairo would agree.
Several years ago, Israel floated the idea of digging a moat along the Philadelphi corridor which would be flooded with seawater, deterring tunnelers who would risk drowning. But that idea was scrapped because of the danger of contaminating impoverished Gaza's underground aquifer.
DANGERS ALONG THE PHILADELPHI
Because the Philadelphi corridor is so narrow -- just a few hundred meters wide in some areas -- it is hard to defend, increasing the risk to Israeli soldiers.
That was a big factor in Israel's decision to leave the corridor when it withdrew troops and settlers from the Gaza Strip in 2005. During the years when Israeli soldiers patrolled the corridor, attacks on them were commonplace.
In 2004, five Israeli soldiers were killed there while preparing to destroy an alleged weapons-smuggling tunnel. Their armored personnel carrier exploded, apparently after being hit by an anti-tank rocket. The Islamic Jihad militant group claimed responsibility for the attack.
(Writing by Adam Entous; Editing by Alastair Macdonald)
