U.S. military pilots who have returned from the fight against the Islamic State in Iraq are confirming that they were blocked from dropping 75 percent of their ordnance on terror targets because they could not get clearance to launch a strike, according to a leading member of Congress.

Strikes against the Islamic State (also known as ISIS or ISIL) targets are often blocked due to an Obama administration policy to prevent civilian deaths and collateral damage, according to Rep. Ed Royce (R., Calif.), chair of the House Foreign Affairs Committee.

The policy is being blamed for allowing Islamic State militants to gain strength across Iraq and continue waging terrorist strikes throughout the region and beyond, according to Royce and former military leaders who spoke Wednesday about flaws in the U.S. campaign to combat the Islamic State.

"You went 12 full months while ISIS was on the march without the U.S. using that air power and now as the pilots come back to talk to us they say three-quarters of our ordnance we can't drop, we can't get clearance even when we have a clear target in front of us," Royce said. "I don't understand this strategy at all because this is what has allowed ISIS the advantage and ability to recruit."

Speaking at the end of the ASEAN summit in Malaysia, Obama also pressed Russian President Vladimir Putin to align himself with the U.S.-led coalition, noting that the Islamic State has been accused of bringing down a Russian airliner last month, killing 224 people.

"He needs to go after the people who killed Russia's citizens," Obama said of Putin.