US airstrikes on ISIS in Syria
US airstrikes on ISIS in SyriaReuters

The US's war on Islamic State (ISIS) carries a hefty price tag, the Pentagon and Defense Department announced Friday.

Since the war - named Operation Inherent Resolve - was announced last August, the US has spent some $2.7 billion in 10 months alone, according to the Associated Press

Of that figure, $1.8 billion has been spent by the US Air Force - with $5 million per day spent on combat flights and reconnaissance. 

Special operations have cost $200 million; the Navy, $438 million; the Army, $274 million for the Army; general military pay, $16 million; munitions, $646 million; and $21 million for intelligence and surveillance operations.

In total, the average daily cost is more than $9 million. 

As of the first quarter of 2015, the total US national debt (public debt) stands at $18.1 trillion.

Despite the hefty investment in the fight against the ISIS terrorists, US President Barack Obama has been sharply criticized for continuing to funnel in more troops while not having a comprehensive strategy.

In a press conference in Germany on Monday, Obama admitted that he doesn't have a "complete strategy" to defeat ISIS.