With their opposing armies massed on either side of the contested border dividing southern and northern Iraq, leaders in Baghdad and the semiautonomous Kurdistan region are warning they are close to civil war — one that could be triggered by Exxon Mobil.

Although leaders on both sides are negotiating a walk back from the brink, they also say their armies could easily be provoked into battle. One of the most sensitive tripwires is Exxon, which is preparing to drill for oil in the disputed territories at the heart of the military standoff. Iraq's two most explosive political conflicts — over land and oil — are primed to combust.

"The prime minister has been clear: If Exxon lays a finger on this territory, they will face the Iraqi Army," said Sami Alaskary, a member of Parliament and close confidant of Prime Minister Nouri al-Maliki. "We don't want war, but we will go to war, for oil and for Iraqi sovereignty."