Many apologists will say that the only aggressive verses in the koran on the topic of war are all defensive.
This is simply not true, here's the facts, sourced from the infallible word of god (koran) itself:
"Then, when the sacred months have passed, slay the idolaters wherever ye find them, and take them (captive), and besiege them, and prepare for them each ambush" -- Qur'an 9:5