A total of about 2,000 air raids have been launched against the militant group, of which the U.S. Air Force carried out 1,768 (88.4%), Agence France-Presse (AFP) reported citing U.S. defense officials.
The report shed light on the dominant role the United States is playing among coalition countries, which include about 50 countries in the fight against the militant group.
But Pentagon officials have insisted the role for Arab and European partners is likely to grow over time.
The Arab states involved in the operation in Syria (Bahrain, Jordan, Qatar, Saudi Arabia and the United Arab Emirates) have been reluctant to divulge details of their participation in the air strikes.
France, Belgium, Britain, Denmark, the Netherlands and Australia have committed aircraft for the effort in Iraq, though their presence has been on a small scale so far.
Other figures released by officials and by U.S. Central Command showed the mounting scale of the air campaign, which began on August 8 in Iraq and was extended into Syria on September 23.
U.S. and coalition aircraft have flown more than 4,800 sorties in the air war, including more than 1,600 refueling runs by tankers, 700 surveillance flights as well as bombing missions, a defense official, who spoke on condition of anonymity, told AFP.
At the current pace, the air operation will soon surpass the air war in Libya that involved more than 7,000 sorties by U.S. and allied aircraft over about six months.
U.S. and other aircraft have dropped about nearly 1,000 bombs in less than two months, officials said. That number, described as “offensive munitions,” includes 47 Tomahawk cruise missiles fired into Syria on the first day of operations there two weeks ago. Each Tomahawk costs more than one million dollars.
The munitions used so far, including numerous precision-guided bombs and missiles, cost about $62.4 million, according to Central Command.
The figure for the cost of bombs used by naval jets flying off a U.S. aircraft carrier was not available.
As of Sunday, there have been more than 260 U.S/ and coalition air strikes in Iraq and at least 93 in Syria.
Meanwhile, the U.S. military is flying Apache helicopters against ISIS militants in Iraq for the first time, exposing U.S. troops to greater risk from ground fire as they help Iraqi Forces battle the Islamist group that has overrun parts of the country.
U.S. troops flew helicopters against ISIS fighters on Sunday and again on Monday as they struck at mortar teams and other units near Fallujah, said a spokesman for Central Command, which is responsible for U.S. Forces in the Middle East.
Source: AFP; Photo: US Air Force