WASHINGTON (CNN) -- Less than a day after a bipartisan group of senators announced a compromise bill aimed at tackling one of the most controversial issues on the docket, it became increasingly clear the immigration proposal will face tough opposition from both sides of the aisle.

The bill would offer the estimated 12 million undocumented immigrants a path to United States citizenship. Some conservatives oppose what they call "amnesty" for illegal behavior, while some liberals call it unfair for limiting opportunities for unskilled workers. Lawmakers and interest groups alike quickly issued statements laying out their positions.

"Basically, when you give somebody benefits, when you give them a pathway to citizenship, when you allow them, starting January 1st, to stay here illegally, when you allow them to work here, that is amnesty. It's nothing but amnesty," Rep. Ed Royce, R-California, told CNN.

The American Immigration Lawyers Association, meanwhile, decried the proposal as "large-scale social experimentation," and singled out the "guest worker" program for precluding a path to permanent residence for new temporary workers.

"A practical solution for the undocumented population is an enormously important step in the right direction," the association said in a written statement. "But the cost of fixing our current problems cannot be the creation of bigger problems in the future."

Senate Majority Leader Harry Reid issued a statement saying that while the agreement "can serve as a starting point" for debate when it gets to the Senate next week, he has "serious concerns about some aspects of the proposal."

Senators who helped draft the agreement pressed for support, arguing that the issue has long ended in a congressional stalemate.