In Daniel 11:40-45, some battles take place, as the beast-king is attacked. It does not say why, but my thinking is because he will be directing all the middle east oil to the EU. Leaving the other parts of the world no choice but to attack him.
Since those battles are near the very end of the 7 years, they will be a prelude to Armageddon, drawing all of the armies of the world into the middle east.