WASHINGTON (AP) — House Speaker John Boehner said Thursday it will be difficult to pass immigration legislation this year, dimming prospects for one of President Barack Obama's top domestic priorities.

"Listen, there's widespread doubt about whether this administration can be trusted to enforce our laws. And it's going to be difficult to move any immigration legislation until that changes," Boehner told reporters at his weekly news conference.

While Boehner called on Obama to restore that trust, he made no mention of his rank-and-file Republicans who were unenthusiastic about a set of broad principles circulated by the leadership last week. The principles included legal status but no special path for citizenship for the estimated 11 million immigrants who live in the country illegally as well as tougher border and interior security.

Republicans are wary of tackling the divisive issue in a midterm election year and angering their core conservative voters who equate any legal status for those who entered the country illegally to amnesty.

White House spokesman Jay Carney conceded that passing immigration reform could take time.

"Nothing like this, nothing as important, nothing as comprehensive ever comes fast or easy in Washington, so this won't be any different," he told reporters, stressing that 2014 still presents the best opportunity.

Conservatives have said they distrust Obama will enforce any new law, citing his waivers and suspensions of provisions on the health care law and his pronouncement in his State of the Union address that he would bypass Congress if lawmakers fail to act on specific issues.

"The president's going to have to rebuild the trust that the American people and my colleagues can trust him to enforce the law in the way it's written," Boehner said.

Carney dismissed Boehner's argument.

"The challenges within the Republican Party on this issue are well-known, and they certainly don't have anything to do with the president," he said.

A group of conservative Republicans said Wednesday that Congress should wait until next year when the GOP may control the Senate and would have greater leverage in any immigration negotiations. Democrats have a 55-45 advantage but are defending more seats this year, including several in Republican-leaning states.

"I think it's a mistake for us to have an internal battle in the Republican Party this year about immigration reform," Rep. Raul Labrador, R-Idaho, told reporters at a gathering of conservatives. "I think when we take back the Senate in 2014, one of the first things we should do next year, after we do certain economic issues, I think we should address the immigration issue."

Labrador's comments were noteworthy as he was one of eight House members working on bipartisan immigration legislation last year. He later abandoned the negotiations.

"This is not an issue that's ready for prime time to move legislatively," said Rep. Joe Barton, R-Texas, who said Republicans should use the principles to begin a dialogue with Hispanics.

It's unclear, however, whether the year leading up to the 2016 presidential election will produce immigration legislation.

The Senate last June passed a bipartisan bill that would tighten border security, provide enforcement measures and offer a path to citizenship for immigrants living here without government authorization.

The measure has stalled in the House where Boehner and other leaders have rejected a comprehensive approach in favor of a bill-by-bill process.

Supporters were optimistic that legislation could move ahead this year when House GOP leaders unveiled their principles last week and Obama indicated that he was willing to consider legalization. Within days, however, Rep. Paul Ryan, R-Wis., said he didn't think legislation could get done, blaming Obama and a lack of trust.

Boehner's pessimistic comments came just two days after Senate Minority Leader Mitch McConnell, R-Ky., told reporters that differences between the Senate's comprehensive approach and the House's piecemeal strategy were an "irresolvable conflict."

"I don't see how you get to an outcome this year with the two bodies in such a different place," McConnell told reporters.

Senate Majority Leader Harry Reid, D-Nev., said Thursday, "don't blame Boehner alone. Because the Senate Republican leader threw cold water on this," a reference to McConnell's comments.

Yet Sen. Chuck Schumer, D-N.Y., who worked to ensure passage of the Senate bill, said "I'm still optimistic that we'll get this done."

Though Obama has threatened to act on his own if Congress did not move on some of his other priorities, Carney signaled that Obama was not prepared to do that on immigration.

"There's no alternative to comprehensive immigration reform passing through Congress. It requires legislation. And the president's made that clear in the past, and that continues to be his view," he said.