WASHINGTON — Shortly before President Barack Obama left for Asia last weekend, aides gave him an ambitious list of potential actions he could order to change the enforcement of federal immigration laws without congressional approval.

Aides said Obama will get final recommendations from his aides as early as Tuesday, and will make his decision – and an announcement – before the end of December.

He could decide to protect as many as 5 million immigrants who are in the country illegally from possible deportation.

Whatever he decides is likely to enrage Republicans, who warned after last week’s midterm elections that any executive action on immigration would “poison the well” on cooperation with the new Republican-led Congress.

Obama told a news conference after the elections that he would announce some changes before the end of the year.

The package under consideration is likely to touch many parts of the immigration system.

It includes tweaks to how work visas are awarded, new instructions on who should be detained for violating immigration law, and pay raises for immigration officers, according to a senior administration official who spoke on condition of anonymity to discuss internal deliberations.

The biggest impact is expected to come from a proposed program that could allow some of the estimated 11 million people in the country illegally to come forward, pay a fee and submit to a background check in exchange for a work permit and a temporary reprieve from deportation, the official said.

That initiative would be similar to the Deferred Action for Childhood Arrivals program, which was created by Obama in 2012 and has so far granted work permits to more than 680,000 people who were brought to the country illegally as children. Those who are approved for deferred action are protected from being expelled from the United States for two years, and the deferrals can be renewed.

Obama is still deciding how far to expand the deferred action program.

Some aides are pushing him to include parents of children who are U.S. citizens, as well as parents of DACA recipients who have been in the country for several years.

If Obama agrees, as many as 5 million people could be eligible to apply under those two categories.

But that number could be pared down if additional requirements, such as proof of a 10-year presence in the U.S., are added.