Top U.S. generals have told President Barack Obama that if the fight against ISIS is to succeed in Iraq, they will need U.S. boots on the ground. The president has so far sent 1,600 ground troops to the Middle Eastern country to assist the Iraqi military in trying to stop the terrorist group, but military leaders in the Pentagon have steadily increased their call for more as the situation on the ground becomes more desperate.

“Our military commanders ... have all laid out scenarios where we need more troops,” said House Armed Services Committee Chairman Rep. Buck McKeon, R-Calif. “If we don’t put boots on the ground, we can’t form the coalition, we can’t retake ground that needs to be taken and held."

So far, the U.S. and coalition forces have conducted a number of airstrikes in strategic areas in Iraq, but they have yet to stem the rise of ISIS in large swaths of the country. The calls from U.S. lawmakers and military top brass have increased since recent reports have claimed that ISIS is slowly descending on key towns near the capital Baghdad. 

“I know that they’ve asked for more than they’ve been given,” McKeon said Wednesday evening on CNN.

The advice comes not long after Obama huddled with military advisors in his first visit to the Pentagon since 2011.

“I would suggest that he listen to his military leaders,” said McKeon, whose blunt words echo much of what is being said among other GOP members. “They would give him the numbers that he should follow.” McKeon’s unfiltered words join a loudening chorus of U.S. lawmakers that are no longer tiptoeing around the subject of ground troops, and are instead stating their case plainly that U.S. ground troops are the only thing that can drive ISIS out of the country.

“I’m not saying that we need to have tens of thousands of troops,” McKeon said. “What I am saying is troops are necessary to call in the targets on the appropriate areas.”