President Obama delivers remarks after meeting with Turkey's president in Antalya on Sunday. (Jonathan Ernst/Reuters)

Just before the terrorist attacks in Paris, President Obama said the Islamic State is not gaining strength in Iraq. The White House now says the massacre will not alter its strategy to counter the radical group.

"We've always understood that our goal has to be militarily constraining ISIL's capabilities, cutting off their supply lines, cutting off their financing," Obama said in an interview with ABC that aired Sunday, using an alternative acronym for the militant group.

"I don't think they're gaining strength," he said. "What is true is that from the start our goal has been first to contain, and we have contained them. They have not gained ground in Iraq and in Syria. They'll come in, they'll leave, but you don't see this systematic march by ISIL across the terrain."

[Obama vows to help France find perpetrators of attacks]

The Islamic State, also known as ISIS, claimed responsibility for the attacks in Paris, which killed 129 people on Friday night. Obama's comments on the status of the battle against the Islamic State were made Thursday.

"What we have not yet been able to do is to completely decapitate their command-and-control structures," Obama said. "We've made some progress in trying to reduce the flow of foreign fighters, and part of our goal has to be to recruit more effective Sunni partners in Iraq to really go on offense instead of simply to engage in defense."

He mentioned the possibility that extremist fighters would exploit security "cracks" to further their goals.

"Al-Qaeda in Yemen, we know, has had plots consistently over the last several years to try to bring down an airliner," Obama said.

[French officials: Manhunt in Europe for at least 1 suspect 'directly involved' in attacks]

"One of the challenges of these international terrorist organizations is they don't have to have a huge amount of personnel. If there is a crack in the system, they potentially can exploit it, and they are looking for these cracks to exploit."

Opening the Group of 20 summit in Antalya, Turkey, Obama said Sunday that the United States would help France in "hunting down the perpetrators" of the attacks. At the same time, Obama aides said the violence does not change the administration's opposition to increasing the presence of U.S. troops on the ground in the Middle East.

“We don’t believe U.S. troops are the answer to the problem,” deputy national security adviser Ben Rhodes told reporters at the summit. “The further introduction of U.S. troops to fully reengage in ground combat in the Middle East is not the way to deal with this challenge.”

— David Nakamura contributed to this report.