American military officials are trying to steer Israel away from the type of brutal, urban combat the US engaged in during the Iraq War, in an effort to keep the Israelis from getting bogged down in bloody, house-by-house fighting as they prepare for an assault on Gaza, multiple sources familiar with the matter told CNN. In helping the Israel Defense Forces game out a number of different strategies to defeat Hamas, US military advisers on the ground in Israel are invoking lessons learned specifically from Fallujah in 2004, one of the bloodiest battles of the Iraq War. Instead of launching a full-scale ground assault on Gaza, which could endanger hostages, civilians, and further inflame tensions in the region, US military advisers are urging Israelis to use a combination of precision airstrikes and targeted special operations raids. They are also drawing on strategies developed during the battle by US-led coalition forces to retake the Iraqi city of Mosul from ISIS, which relied more heavily on special operations forces. Like Hamas, ISIS built tunnels throughout Mosul and used civilians as human shields, and the fight to retake the city was harder and more drawn-out than anticipated. To help deliver this message, the Biden administration has sent a three-star Marine Corps general to counsel the IDF on planning its tactical assault. Gen. James Glynn, the former commander of Marine Forces Special Operations Command, has significant experience with urban warfare in Iraq, particularly in Fallujah, where he commanded troops during some of the bloodiest fighting there between US forces and insurgents, officials said. Since the Hamas attack on Israel on October 7, the US has grown increasingly concerned that Israel's strategy to move into Gaza with a large number of ground troops is only half-baked and could lead to a bloody and indefinite occupation by Israeli forces in the Gaza strip, officials said. The US has also urged Israel to think about how a full-scale ground invasion could endanger the more than 200 hostages still being held by Hamas in Gaza, the civilians who have no way out, and what comes after an invasion in terms of governance of the millions of Palestinians in the Gaza Strip. "I don't think Israel has a strategy for what they do next" in terms of executing a full-blown ground invasion, one source familiar with concerns within the Biden administration said. Israel's objectives and strategy have been a central point of discussion between American and European officials over the course of the past week, people familiar with the matter said, as the allies work to coordinate an approach to Israel. President Joe Biden spoke Sunday with the leaders of France, Germany, Italy, Canada and the United Kingdom about the crisis, hoping to align on the key issue of supporting Israel while also gaining clarity on its path forward. CIA director Bill Burns has been on back-to-back phone calls with partners and allies in the region, including the Israeli intelligence service Mossad, the US' Arab partners and its NATO allies, in an effort to keep the conflict from spiraling into a regional conflagration and to work to ensure the safe release of hostages still held by Hamas. Biden has encouraged Israeli Prime Minister Benjamin Netanyahu in their recent conversations to think through how such an invasion would unfold, and what the exit strategy would be, officials said. Biden and Netanyahu spoke on Sunday and again on Monday, and in those conversations, the president sought to try to "get [Netanyahu] to use his head, not his heart," a source familiar said. Still, the sentiment across much of the US government is that Israel is almost certain to proceed with a full scale ground invasion, in large part because domestic sentiment inside Israel is so enflamed that Netanyahu may feel he has no other choice. "We stand before the next stage, it is coming," Netanyahu told the Israel Defence Forces' Yahalom unit on Tuesday, according to a press release from Netanyahu's office. "You know it and you are part of it; you are part of the vanguard." "We have only one mission – to smash Hamas," he added. "We will not stop until we complete it, with your help." In 2014, Netanyahu set out to debilitate Hamas with the last ground invasion into Gaza. While that war dealt Hamas a significant blow, it was a huge challenge and failed to dislodge the organization from the coastal enclave. Despite numerous rounds of escalation and conflict with Gaza, Israel hasn't attempted another incursion since. A senior Israeli official said that the US is not telling the Israelis to deescalate or refrain from crossing any "red lines." "They are saying while you fight the war – pay attention to all of these dimensions," the official said. "The US has its own experience for fighting wars in urban areas, Fallujah, in Mosul and so on. ... And so you [the United States] also have some experience in such a situation. And it's always good to share experiences, among friends." "In all of our conversations, we continue to talk to them about the importance of having meaningful goals, meaningful objectives and a plan to achieve those objectives," State Department spokesperson Matthew Miller said Monday. "We've been engaged in a number of levels. The Pentagon has been engaging in military-to-military channels about what their operations might look like." Secretary of Defense Lloyd Austin speaks to Israeli Defense Minister Yoav Gallant daily about Israel's military needs and strategy, an official said, and one frequent point of discussion is how the extensive network of tunnels Hamas has built inside Gaza will complicate a ground invasion, an official said. "The message is, have you really thought this through?" a Western diplomat said. "Coming from friends who have in recent years gotten themselves embroiled in counterinsurgency scenarios in hostile territory, we can tell you need an exit plan and it gets ugly quickly." Gallant on Tuesday told an elite commando unit of the Israeli army that Israel must destroy Hamas and warned that the war is still in its early stages. "Prepare for the tasks to come, the war is just starting. And unfortunately, we'll have to pay a price," Gallant said. "Prepare well, be ready – physically and mentally, with equipment and means. We'll get to the field and will destroy Hamas. Literally. Otherwise, we couldn't exist here," he added. Another key US and allied message to Israel has been that any invasion must abide by international humanitarian law. A Western source told CNN that Israel is being cautious in its planning for a ground incursion because it realizes if it gets it wrong it will lose the moral high ground. They acknowledged that "the battle for the moral high ground" is already difficult for Israel, pointing to the quick condemnation directed at the Israeli government over the hospital blast, which Israel said was a Palestinian Islamic Jihad misfire. On Tuesday, French President Emmanuel Macron visited Israel and offered support for Netanyahu, but warned: "This fight must be without mercy, but not without rules." Macron also suggested forming an international coalition to counter Hamas, akin to the US-led coalition meant to defeat ISIS formed during the Obama administration. "The idea is to draw on the experience of the International Coalition against [ISIS] and see what aspects can be replicated against Hamas," a French official told CNN. "As a reminder, the International Coalition against [ISIS] is not limited to operations on the ground, but also involves training Iraqi forces, sharing information between partners, and combating the financing of terrorism." But a Western official familiar with the matter said forming any international coalition would depend, in large part, on gaining more clarity from Israel on the goals of its ground invasion. Israel's ambassador to the UN, Gilad Erdan, told CNN last week that Israel has "no interest" in occupying Gaza, although Israeli officials have warned the operation there will be lengthy. "Our advice to them isn't 'Don't do it,' because we completely respect their right to go after Hamas and that means going after them wherever they are," a NATO defense minister previously told CNN. "So it's not 'Don't do it,' but it is 'Think about what happens and have a strategy, not just a tactical maneuver.' We expect Israel to act within international humanitarian law, but we understand that they're dealing with an enemy here." — CNN