The progress seen in the pitched battle between Iraqi troops (supported by U.S. forces) and ISIS for control of the northern Iraqi city of Mosul may seem like the light at the end of the dark Islamic State tunnel. But that hopeful glimmer may just be a geopolitical freight train coming the other way.

While Iraqi forces have taken back the eastern part of Mosul, the battle reportedly continues to rage across the Tigris River in the western section — with vicious street to street and door-to-door fighting with Islamic State militants.

Iraqi Prime Minister Haider al Abadi told Fox News on Sunday that ISIS would be militarily defeated in Iraq in the next few weeks, but that could be a bit optimistic due to the challenges of taking back Iraq’s second-largest city.

Indeed, ISIS essentially holds an untold number of “Moslawis” hostage in a city where 2 million once lived; worse, many are used as “civilian shields.” This unquestionably complicates — and slows — anti-ISIS military operations.

The Islamic State has also reportedly been using snipers, suicide bombers, mobile or immobile car bombs, booby traps, mortars and even hobby-sized drones carrying “bomblets” to some effect on the urban battlefield.

Nothing — no matter how heinous — is off limits for ISIS.

It’s been a tough slog for the Iraqi military since last October, making it no surprise that the Pentagon is sending more U.S. troops (approximately 200) to Iraq to advise and assist in the fight with the Islamic State.

But whether it’s a few weeks, or few months — or more — to defeat ISIS in Mosul, the battle for Iraq’s future is far from decided. Iraq won’t be a province of the Islamic State caliphate, but the country’s future likely won’t be settled soon, either.

For instance, it’s very unlikely ISIS will wave the white flag of surrender in Iraq after Mosul. Rather, it will wave its black flag of militant extremism, likely manifested in some level of violent insurgency across the country. Its ideology will survive Mosul.

Ethnic and religious troubles will persist beyond those generated by ISIS, too.

Iraq’s Sunni Kurds may not want to be governed by Prime Minister al-Abadi’s Shiite Arab central government after ISIS is (largely) defeated. Irbil could push for full independence from Baghdad — not just regional autonomy.

Iraq’s Sunni Arabs are also going to demand changes from the ruling Shiite Arabs in Baghdad on the conditions that led to instability — and the rise of ISIS. Paramilitary Shiite militias will also have to be tamed.

Outside powers have a stake, too.

Turkey is keen on protecting its interests in Iraq, which includes co-religionist Sunnis, minority Turkmen and concerns about the rise of a Kurdish state. Remember: Mosul was once part of the Ottoman Empire.

Victory in Mosul — certainly a major blow to ISIS since it declared its caliphate there — may be the end of one big challenge, but it’s also the beginning of many other tough tasks that Iraq will need to take on.