Weeks into the war, how much closer is Israel to its goal?

Israel's stated military objective from the outset has been to destroy Hamas, militarily and politically. How much closer is it to achieving that goal, and is it achievable?

As far as Israel is concerned, these are still early days - it has repeatedly said that this operation will be long and difficult. One senior Israel Defense Forces (IDF) official who spoke to the BBC used the analogy of a boxing match: "This is just round four of 15."

No-one in Israel is saying exactly how long the war will last. Some point to the fact that it took nine months for Western-backed Iraqi forces to retake the city of Mosul from the Islamic State (IS)group in 2017. Israel may want to carry on fighting for several more months, though it may not control the timetable, as international pressure for pauses in the fighting or even a ceasefire are growing.

Military losses

So far, Israel says it has carried out more than 14,000 strikes and killed dozens of high-value targets, including senior Hamas commanders. Each of those strikes will have involved multiple weapons. Yaakov Katz, a military expert and former editor of the Jerusalem Post newspaper, says Israel has already fired more than 23,000 munitions.

As a comparison, at the height of the battle for Mosul, Western allies dropped around 500 bombs a week on IS targets.

More than 10,800 people in Gaza have been killed since the start of the war, according to the Hamas-run health ministry, including more than 4,400 children.

The military says its ground forces have successfully divided the Gaza Strip between north and south, and that its troops have surrounded Gaza City. It claims they are now "deep in the heart of the city", though that is still far from claiming control. Hamas has denied that Israeli forces have made any significant gains or pushed deep into Gaza City.

This initial phase of Israel's ground offensive appears to be going according to plan with its aim of isolating Hamas, and the cost to Hamas is likely to have been high. Estimates at the start of the war suggested that the group had between 30,000-40,000 fighters.

One senior Israeli defence source told the BBC that about 10% of that total - 4,000 fighters - have been killed. Such estimates are impossible to verify and should be treated with caution, but the sheer scale of Israel's bombing campaign will have already degraded Hamas's ability to fight.

Maps of Gaza City and a timeline of how Israeli forces surrounded the city over four weeks

In contrast, Israeli military losses appear to have been relatively low. Israel says 34 of its soldiers have been killed since ground operations began. Yossi Kuperwasser, an Israeli intelligence and security expert, says the military is conducting its ground operations "more carefully and cautiously" to avoid heavy casualties among its troops.

It's still not clear how much of Hamas remains in the north, how many fighters may still be hiding in tunnels, or how many might have melted into the local population who have fled south.

The tunnels still present a significant challenge to Israel. Its forces are trying to blow up what tunnels it finds, rather than engage in fighting underground.

Urban warfare challenges

More obvious is Israel's significant advantage in terms of intelligence and military capabilities. It can intercept communications and even turn off Gaza's mobile phone and internet networks. It has complete air superiority with Israeli jets and drones able to monitor every movement on the ground, but not below the surface.

One senior Israeli defence source told the BBC that they were still identifying more than 100 new targets each day, although that list is likely to diminish the longer this war goes on. The longer it lasts, the more it will have to rely on troops on the ground to identify and eliminate resistance.

Justin Crump, a former British Army officer who now runs Sibylline, a risk intelligence company, says Israel appears to be making reasonable progress given the density of the terrain, but "they're now going to encounter the more heavily defended urban areas of the city".

Israeli troops are better equipped and well-trained, but urban warfare can still prove difficult for the most advanced militaries.

So far, close-quarters fighting on the ground appears to have been limited, and is certainly nothing on the scale of the urban warfare that's been taking place between Russia and Ukraine in cities like Bakhmut. Much of the videos released by the IDF show that it is instead relying on tanks and armour.

Neither has Israel committed all its forces. Some estimate that it may have as few as 30,000 troops inside Gaza so far. That's a relatively small proportion of Israel's total - 160,000 active military personnel plus 360,000 reservists.

Justin Crump says the question is how many of its infantry is it willing to commit to clearing every building and the warren of Hamas tunnels?

Israel could instead chose to target Hamas strongholds. He believes Israel will try to avoid block-by-block fighting, not least because it could lead to very heavy casualties. It would also certainly jeopardise the lives of more than 200 hostages.

A post-invasion plan

Which raises the question as to whether Israel's stated war aim - destroying Hamas - is really achievable. Even senior Israeli officials recognise that destroying an ideology with bombs and bullets is impossible.

Some of the group's leadership isn't even in Gaza. Mr Katz says that if elements of Hamas can survive this war, then they could still claim "because we're still here, we've actually won".

For that reason, Mr Crump believes Israel's war aims could shift from destroying Hamas to punishing it, to make sure it there is no repeat of the 7 October attacks.

Israel is also under increasing pressure to explain what happens next, especially from the US.

One Israeli defence source said Winston Churchill wasn't thinking about a Marshall plan to rebuild Germany, when he helped launched the allies invasion on D-Day in the Second World War.

But wars are rarely won without a plan post-invasion - something that's been completely absent in Israel's military operation so far.

-bbc