I think its more of 4th gen of war... yes artillery shelling with drone assistance may help. As civilians are there (let me include that)..
Only infantry can capture then on full assault, but brick by brick. Modern weapons will stop any tank or amroured advancement which will lower the moral of strike force
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I think you misunderstand what 4th Generation warfare mean.....
In Warfare Science, 4th Generation warfare define a decentralised form of warfare, meaning there are no nominated factor of defence or offence force, the line between military and politic have been fused together.
Not all insurgency are classified as 4th Generation warfare, however, one very solid part of any 4th generation warfare is the local insurrection.
The meaning of decentralised warfare means there are both component of nominal fighting and insurgence in the mix, basically is an insurgent with its own national army.
When we classified insurgency, we see that it is either an army without local support or an resistance movement without an armed support, they can be peaceful or violent. But 4th Generation warfare bring a third element into the mix, which would be an organised fighting force. When you introduce that into the insurgency, then you have a 4th gen war at your hand.
Like all 4th gen war, the only way you can win is first by defeat the garrison, and start pacification. And if you are not talking about a local partisan but an foreign invading army, then it is nearly impossible to win in a 4th gen war. Anyone can fight off an garrison, but you need local knowledge to pacify the insurgency part of the element. And most likely the reason of insurgency was rooted at that invading foreign army in the first place.
But the question is, is your scenario point to a 4th Generation war??
It's too little to say, since you say the invader are technological more advance than the defender, but then negate that effect by saying the defender process modern weapon that can demoralise the invader.