Washington: The United States' Central Intelligence Agency (CIA) on Thursday predicted that Islamic State militant group has about 20,000 to 31,500 fighters on the ground in Iraq and Syria.
This figure is much higher than the previously estimated 10,000.
"CIA assesses the Islamic State of Iraq and the Levant (ISIL) can muster between 20,000 and 31,500 fighters across Iraq and Syria, based on a new review of all-source intelligence reports from May to August," CIA spokesman Ryan Trapani said in a statement.
The development came a day after US President Barack Obama announced that his country would launch air strikes against IS militants in Syria and expand the operations against them in Iraq.
Vowing not to allow the IS militants 'a safe haven', Obama said he would target the jihadists 'wherever they are'.
Arab nations have supported the announcement by Obama, assuring the US their support in operations against the IS which has become a global threat.