Tel Aviv, Oct 24 : US President Joe Biden's administration is reportedly concerned that Israel lacks achievable military goals for its operations in Gaza, leading US officials to believe that the Jewish nation's military is not yet ready for a ground incursion, Times of Israel reported. US officials have held marathon meetings and phone calls with their Israeli counterparts to discuss the ground operation, which many thought the Israel Defense Forces (IDF) would have launched by Monday -- 17 days after the October 7 Hamas massacre, in which over 1,400 people were slaughtered in Israel and roughly 220 were taken hostage into Gaza, The Times of Israel reported. In the interim, the IDF has maintained a near-constant aerial bombardment it says is targeting Hamas terrorists and infrastructure, which has left thousands dead. Defense Secretary Lloyd Austin has held near-daily phone calls with his Israeli counterpart, Yoav Gallant, during which the former has urged the importance of carefully considering how IDF troops conduct the incursion in Gaza, where terrorists will operate from tunnels and densely populated areas, The New York TimesreportedMonday, citing unnamed US officials. In a Sunday interview with ABC News, Austin said the ground invasion Israel plans to launch could well take longer than the amount of time it took for the US to remove the Islamic State from power in Mosul, Iraq, when he was the head of the US Army's Central Command. 'Urban combat is extremely difficult. It goes at a slow pace,' he said. 'This may be a bit more difficult because of the underground network of tunnels that Hamas has constructed over time and the fact that they have had a long time to prepare for a fight." US officials told The New York Times on Monday that Israel must decide whether it wants to eliminate Hamas terrorists through a combination of surgical strikes and targeted raids by special forces, as the US did with Iraqi and Kurdish soldiers in Mosul in 2017, or to launch a more expansive ground invasion, as US troops did with Iraqi and British forces in Fallujah in 2004. Israeli cabinet ministers have repeatedly pointed to Fallujah as an example of the kind of operation they want to see the IDF launch in Gaza, The Times of Israel reported. Both strategies will result in heavy losses, though the Fallujah model would be far bloodier for both soldiers and civilians, the US officials told The New York Times, adding that many in the Pentagon accordingly prefer the Mosul blueprint. /IANS