WASHINGTON — An emboldened House Speaker John Boehner warned Thursday that President Obama will “burn himself” if he takes executive action on immigration reform over Republican objections.

Yet Boehner declined to promise that Republicans will offer their own immigration solutions, now that the party controls both houses of Congress, acknowledging that the issue has vexed his leadership.

The White House has run out of patience with Boehner’s fits and starts on immigration reform, and Obama reiterated this week at a post-election news conference that he will act on his own by the end of the year unless Congress moves.

Doing so would “poison the well,” Boehner said in his first remarks since Republicans’ Election Day sweep, at a time when lawmakers want to rebuild trust with the administration. Republicans will have their biggest majority in the House in nearly a century.

“When you play with matches, you take the risk of burning yourself — and he’s going to burn himself if he continues to go down this path,” the speaker said of the president.

Before year’s end, the administration is expected allow as many as 5 million immigrants to stay in the country without fear of deportation. Many of those protected would likely be parents of American citizens.

Incoming Republican Senate Majority Leader Mitch McConnell said this week that Obama’s actions would be like “waving a red flag in front of a bull” — enraging Republicans.

Republicans have repeatedly failed in their own efforts to pass immigration legislation because of party infighting over the best approach.

A bipartisan Senate bill crafted with top GOP leaders, including Sen. John McCain, R-Ariz., fizzled in the House over the provision to let immigrants here illegally remain in the U.S. if they are law abiding, learn English and pay back taxes and fines.

The crisis of young immigrant children at the border last summer, Boehner said, left Congress stalled on how best to to handle the issue.

But when pressed why House Republicans did not pass a bill in the previous 18 months of the session, Boehner demurred.

“I could regale you with all of my challenges of trying to get members on both sides of the aisle to deal with this. They were numerous,” Boehner said.