Israeli soldiers are equipped with some of the most advanced personal weaponry available to a modern military, but they nonetheless face great danger on the ground in Gaza.
The Islamist militant group Hamas, masters of asymmetrical warfare, has several key weapons that can inflict heavy casualties on an invading force, despite being overmatched. These weapons were not of great concern to Israel when it was attacking from sea and air. But the danger has increased exponentially since Israel launched its ground assault over the weekend.
One significant danger every Israeli soldier faces in Gaza is a foe who is yearning to give up his life. Hamas has built a force of willing suicide bombers whose explosive vests are typically packed with an assortment of shrapnel to raise the casualty rate among their targets.
While Israeli soldiers are prepared to die in the defense of their country, they are also trained to survive. The suicide bomber is, therefore, a weapon available only to one side of this conflict.
Hamas has been talking tough in the face of superior military power; its leaders have vowed to inflict massive casualties.
"Gaza will be your cemetery," and "we will fight until the last breath," Hamas spokesman Ismail Radwan said in a written statement.
As Israel pushes into Gaza on the ground, it does not know exactly what weapons -- and how many of them -- Hamas possesses.
"We don't know what has been smuggled into Gaza," said David Schenker, a senior fellow at the Washington Institute and a former Pentagon official specializing in Middle East issues.
"Syrians and Iranians have supplied Hamas with training and weaponry," Shenker said, pointing to a variety of weapons used during Israel's 2006 war in Lebanon as examples of what Israeli ground troops may face in Gaza.
"In Southern Lebanon, we saw the use of Improvised Explosive Devices (IEDs) that disabled several Merkava tanks and killed the soldiers inside," Shenker said in a phone interview with FOXNews.com.
"In Lebanon, we confirmed the use of the Kornet anti-tank system," Shenker said, referring to a series of Russian manufactured wire-guided missile systems. When U.S. forces invaded Iraq in 2003, the relatively small and easy to use Kornet anti-tank system reportedly disabled several American tanks, though Russia denied having sold the armor-piercing weapons to Iraq.
In Lebanon, between 46 and 50 Merkava main battle tanks (of the 400 deployed) were hit by anti-tank weapons, according to Western sources. In this case, too, Russia denied selling arms to either Syria or Hezbollah.
The weapons systems flowed into Lebanon more easily than they can in Gaza, where the borders are under stricter surveillance. But a network of underground tunnels used for smuggling has military analysts questioning exactly what weapons the militants in Gaza may possess.
Hamas lacks air, sea and armor assets, so it has little hope of successfully challenging Israeli forces on an open battlefield. But a modern military's overwhelming advantage dwindles quickly in an urban environment.
Hamas, Schenker said, has claimed possession of American-manufactured weapons the State Department gave to its political rival, Fatah. The weapons, intended to help bolster the precarious security situation of the Fatah government, now could be used to fight the Israeli military.
Al Aqsa Television has broadcast footage of Hamas gunmen brandishing American assault rifles, rocket-propelled grenades, rocket launchers and ammunition the U.S. reportedly provided to Fatah. The captured weaponry is said to include 7,400 American M-16 assault rifles and 800,000 rounds of bullets.
Both the rocket-propelled grenades (RPG) and M-16s would enable Hamas fighters to aim and hit a target from a broader distance, but the danger for the Israelis increases as its fighters draw closer.
Israeli soldiers have the advantage of specific urban operations training, a modern communications system, personal weapons like night vision goggles (NVGs) and the Israeli designed Tavor, a highly accurate automatic assault rifle conceived specifically with close-quarter combat in mind.
The Israelis also possess a variety of hand-grenades and explosives to breech obstacles and eliminate the enemy, but they must be mindful of civilian casualties. For this reason, Israeli soldiers may need to use flash/stun grenades that produce an intense burst of light and a piercing noise, instead of simply relying on heavy firepower to destroy any dwelling.