WHILE I WAS DRIVING MY 2013 KIA OPTIMA HYBRID THIS MORNING. WHILE DRIVING, I SUDDENLY GOT A WARNING MESSAGE THAT SAID "HYBRID SYSTEM FAILURE STOP SAFELY DO NOT DRIVE". I PULLED OVER AND SMELLED WHAT SEEMED TO BE FIRE, BUT SAW NOTHING. I CALLED MY FIANC TO LET HIM KNOW WHAT WAS GOING ON AND THE CABIN STARTED FILLING WITH SMOKE. I JUMPED OUT OF THE CAR AND POPPED THE TRUNK. THERE WERE FLAMES SHOOTING OUT OF THE HYBRID SYSTEM. THE FIRE WAS EXTINGUISHED, THE CAR IS NOW SITTING IN A TOW YARD. I TAKE VERY GOOD CARE OF MY CAR. THERE IS NOTHING THAT I WOULD HAVE DONE OR COULD HAVE DONE TO CAUSE THIS.