(AP) - President Barack Obama says he plans to help immigrants living illegally in the United States "get legal" without any action from Congress. And he promises to curb a system that he describes as deporting immigrants improperly. But the White House is vague about the changes the president is expected to announce soon.

What can Obama actually do without the cooperation of Capitol Hill?

Under current law, the president can direct immigration authorities to temporarily shield particular immigrants from deportation and give them permission to work in the country legally.

But the president cannot give immigrants living in the country illegally green cards, visas or just about any other path to a permanent legal immigration status. Only Congress has that authority, and so far lawmakers have shown little interest in remodeling the country's complex legal immigration system.

Still, Obama's hands are not tied. Two years ago, he launched the Deferred Action for Childhood Arrivals, or DACA, program that lets young immigrants who came to the U.S. as children stay in the country without fear of deportation for two years. So far, more than 610,000 have benefited from that program.

The president can also allow some people living in the country illegally to "parole in place," during which time they can apply to live in the country legally. Once they receive permission to stay, they can later apply to change their immigration status and possibly win a green card. An immigrant who holds a green card is a legal permanent resident and can eventually apply to become a U.S. citizen.

In the past, the "parole in place" designation has been limited to helping very small numbers of immigrants stay in the United States, including spouses, parents and children of U.S. military personnel.

A U.S. official who has been briefed on parts of the president's executive action plan said the administration estimates that as many as 7 million immigrants currently living in the country illegally could benefit. That group includes parents of U.S. citizens and those young immigrants already protected from deportation.

The official spoke on condition of anonymity because the official was not authorized to discuss the plan before the president's announcement.

Obama's descriptions of what he plans came in a news conference and separate television interview in September as the White House announced that he would not roll out any executive immigration actions until after the midterm elections.

The White House has declined to say what Obama meant by "be legal" or "get legal."

The president earlier this month, on CBS' Face the Nation, said that he intended to "do what I can do through executive action," but he added, "It's not going to be everything that needs to get done."

The president said the current immigration system doesn't work and "we're deporting people that shouldn't be deported. We're not deporting folks that are dangerous and need to be deported."

Yet those comments undermine statements of his own immigration enforcement agency, Immigration and Customs Enforcement, which routinely highlights its efforts to find and deport criminal immigrants.

Internal ICE documents obtained by The Associated Press describe an agency effort that "prioritizes identifying and removing criminal" immigrants. The report notes that about 56 percent of the 315,943 immigrants sent home during the 2014 budget year that ended in September were criminals.

Obama has not always made a case for broad executive action, arguing in the past that his ability to act on his own was limited.

In a February 2013 Google Hangout session, he was asked what he would do to ensure that more people were not deported. "The problem is that I'm president of the United States; I'm not the emperor of the United States," he said. "My job is to execute laws that are passed."

But on Sunday, during a news conference in Brisbane, Australia, he defended his decision to take matters into his own hands in the face of inaction in Congress.

"I can't wait in perpetuity when I have authorities that, at least for the next two years, can improve the system, can allow us to shift more resources to the border rather than separating families, improve the legal immigration system. I would be derelict in my duties if I did not try to improve the system that everybody acknowledges is broken."

The Homeland Security Department's No. 2 official, Alejandro Mayorkas, has said previously that the president can help immigrants in the country illegally "get legal" with a program similar to the one now providing protection from deportations for young immigrants.

Mayorkas previously ran U.S. Citizenship and Immigration Services, which manages immigration benefits cases and programs including DACA. He said that program didn't give young immigrants legal status, but it provides a "lawful presence" and allowed them to legally work.

"Legal status" in immigration is a specific phrase that means immigrants have visas or green cards that allow them to live and work legally. "Lawful presence" can mean someone has a visa, but it can also extend to other immigrants who have temporary permission to stay, even though they either overstayed their visa or entered the country illegally.