The Mongols under Genghis Khan had a technique that was highly effective.
They would invest a city and offer them the chance to surrender. If they did not, the entire city would be destroyed and the inhabitants put to the sword. Subsequent cities usually gave up without a fight.
So how does this fit into the modern war scenario?
Easy. You come up to the first apartment building and announce via loudspeakers that the building will be destroyed if everyone inside doesn't come out at once. If they don't come out, Destroy the building completely, utterly.
Then go on to the next building. They aren't stupid. They'll get the idea real quick.
Bingo! No house-to-house fighting.

troll