The Sunni radical group Islamic State in Iraq and Syria overran the Syrian province of Deir Ezzour Thursday and the al-Omar oil field, the country’s richest producing area.
The field has a production capacity of 75,000 barrels per day.
ISIS now controls about 20,000 square miles of territory from Syria’s Aleppo Province to about 40 miles west of Baghdad in Iraq.
A week ago, the group announced the establishment of the Islamic State or Caliphate that doesn’t recognize existing national borders.
ISIS declared itself the ruling authority over all Muslims and called on them to rise up in a new Jihad.