Sen. Marco Rubio acknowledged Tuesday on a conservative radio talk show that the Gang of Eight’s comprehensive immigration reform bill won’t likely pass the Republican-led House.

The comments from Rubio, perhaps the most influential congressional Republican on immigration, illustrate the challenges facing the prospects for reform after months of private negotiations by a bipartisan coalition of senators produced a wide-ranging, 844-page bill.

“The bill that’s in place right now probably can’t pass the House,” Rubio told Mike Gallagher, a nationally syndicated talk show host. “It will have to be adjusted, because people are very suspicious about the willingness of the government to enforce the laws now.”