The number of Israeli soldiers killed in Gaza is already double that of the 2014 ground offensive, an indication of how deep the Israeli military has penetrated the enclave, as well as Hamas's effective use of guerrilla tactics and new weaponry.
Israeli military experts, an Israeli commander and a Hamas source described to Reuters how the Palestinian group uses large stockpiles of weapons, knowledge of the terrain and a vast network of tunnels to turn Gaza's streets into a deadly maze.
They have weapons at their disposal, ranging from drones equipped with grenades to anti-tank weapons. According to Israeli figures, since the start of the Israeli ground campaign in late October, around 110 Israeli soldiers have been killed as tanks and infantry stormed the towns and refugee camps. About a quarter of the victims were members of tank crews.
In 2014, 66 Israeli soldiers were killed in the clashes, when Israel launched a limited three-week ground offensive, but the goal then was not to destroy Hamas.
"This war cannot be compared to the one in 2014, when our forces did not operate deeper than a kilometer inside Gaza," Yakov Amidror, a retired Israeli major general and former national security adviser, told Reuters.
He said that the army "has yet to find a good solution for the tunnels", a network that has been significantly expanded over the past decade. In recent weeks, it has been mentioned that the Israeli army is planning to pump seawater and flood the Hamas tunnels.
The Israeli offensive was launched after the incursion of members of Hamas on October 7, who killed 1200 people in Israel and kidnapped over 200 hostages. Since the start of the offensive, nearly 18.000 people have been killed in Gaza, prompting international calls for a ceasefire.
"It was a challenge from the first day," Ofir Falk, adviser to Israeli Prime Minister Benjamin Netanyahu, told Reuters, stressing that the offensive came at a "high price" for Israeli soldiers. "We are aware that we will likely have to pay an additional price to complete the mission."
Hamas released footage on its Telegram channel this month showing fighters launching rockets at armored vehicles from buildings. In one of the images, released on December 5, a periscope-like camera emerges from a tunnel to film an Israeli camp where conscripts are resting. The post said the camp was later hit by an underground explosion.
Reuters could not confirm the authenticity of the footage.
A Hamas source, who spoke to Reuters on the condition of anonymity, said fighters attack from ambushes "taking advantage of the terrain we know better than anyone else," or often move through tunnels.
"There is a huge difference between our power and theirs, in this respect we are not fooling ourselves," he told Reuters.
Hamas has not announced how many fighters it has lost, and the Israeli military says at least 7000 have been killed. The group rejects Israel's claims, saying the figure includes a large number of civilians.
An Israeli commander, who fought in 2014, said that the larger scale of the operation means more soldiers on the ground, which in a certain way gives Hamas "the advantage of the one who defends himself", so that a greater number of Israeli soldiers are to be expected.
The Israeli army posted footage on social media showing roads bulldozed through buildings to avoid existing roads that could be mined. Such tactics were also used in 2014, Reuters points out. Even in some neighborhoods in the north of Gaza, where buildings have mostly been razed to the ground, there is still fierce resistance.
"Hamas has taken major steps to strengthen its forces since 2014," Eyal Pinko, a former senior official in the Israeli intelligence service, told the British agency.
He said that some advanced weapons, such as Russian "cornet" anti-tank missiles, were smuggled into Gaza with the help of Hamas's ally Iran. However, he said that Hamas has also perfected making other weapons in Gaza, such as RPG-7 grenades, and that the militants now have larger reserves of ammunition.
Hamas posts say the group possesses a “trandem” anti-tank weapon with two armor-piercing charges. Hamas footage showed large explosions after the vehicle hit. Israeli experts, however, claim that the explosion does not necessarily mean that the vehicle was destroyed, but that it was caused by a defense system that exploded to stop the missile.
Ashraf Abelhul, the editor of the Egyptian newspaper "Al Ahram" who previously worked in Gaza, said that the militants have advanced in the use of advanced weapons as well as "missiles of local production".
However, he said that Israeli drones and other tactics undermine their ability to surprise the enemy, even in urban areas. "The fight in the city has become more difficult" for the militants, he said.
The Israeli military released a video this month that it claimed showed militants emerging from a tunnel under the bombed building, before it was hit by a missile.
"Hamas may have new weapons and tactics, but in principle it remains a guerrilla resistance movement," Alexander Greenberg, a former Israeli military intelligence officer who now works at the Institute for Strategy and Security in Jerusalem, told Reuters.
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