White House deputy press secretary Josh Earnest on Tuesday declined to rule out the possibility President Obama would use executive order to enact immigration reforms.

“I don't want to speculate about what sort of actions the president might or might not take,” Earnest told reporters traveling with the president in California.

The Obama spokesman though stressed that the president wanted Congress to act on the contentious issue.

“The president is often asked if there is an executive action that would substitute for that comprehensive immigration reform legislation. There is not,” he said.

Earnest’s comments come a day after Obama responded to liberal critics who have urged him to use executive action to bypass legislative opposition on immigration and other issues, including workplace discrimination.

Responding to a heckler at a DNC fundraiser who kept shouting “executive order,” Obama said he could not just "nullify Congress."

"That's not how it works," said the president. “We've got this Constitution, we've got this whole thing about separation of powers. So there is no shortcut to politics, and there's no shortcut to democracy."

Obama has made immigration reform a second-term priority, but a comprehensive bipartisan bill passed this summer by the Senate has stalled in the GOP-controlled House. Speaker John Boehner, R-Ohio, said the Senate bill was dead on arrival and House Republicans say they will only address immigration reform piecemeal.

“We have been very clear that the problem that the president is trying to solve here is one that can only be solved with the Congress, and that problem is an immigration system that everybody acknowledges is broken,” said Earnest.

Earnest said lawmakers must address border security, reform the legal system, change the employer-enforcement system and guarantee a pathway to citizenship for the illegal immigrants already in the country.

“Those are four principles that cannot be achieved unilaterally through executive action,” he said.

The president in 2012 issued an executive order barring the deportation of some young illegal immigrants, but immigration-reform advocates are pressing him to do more to prevent all deportations.