(CNN) President Donald Trump on Wednesday opened the door to citizenship for young undocumented immigrants who came to the US as children, the first time he's explicitly said he'd accept a pathway to citizenship for them.

"We're going to morph into it. It's going to happen at some point in the future," Trump said of the immigrants eligible for some version of the Obama-era Deferred Action for Childhood Arrivals program, which Trump has ended but is urging Congress to replace. He said the time frame would be over 10 to 12 years. The President made his comments to a group of reporters who were meeting with White House chief of staff John Kelly at the White House.

Trump called it an "incentive" for the immigrants, who largely have known no other country beside America, to work hard and do a "great job."

"If they do a great job, I think it's a nice thing to have the incentive of, after a period of years, being able to become a citizen," Trump said.

In the meantime, he said DACA recipients should not be worried about being deported if their status expires.

"Tell them not to be concerned, OK?" Trump said. "Tell them not to worry about it. We're going to solve the problem. Now, it's up to the Democrats, but they should not be concerned."

Whether to include a pathway to citizenship -- as opposed to stopping at legal residency -- for DACA recipients has been a key sticking point between hardline conservatives and moderate Republicans and Democrats, on the other.

Trump's extended comments on what he wants in an immigration deal were some of the most substantive to date, after lawmakers have asked the White House and President for months for a clear outline of what he could -- and couldn't -- support.

"I like him! I like Schumer! I grew up with Schumer," Trump told reporters.

Reactions to Trump's DACA comments

Sen. Lindsey Graham, a Republican from South Carolina who's been a key part of congressional immigration negotiations, immediately praised Trump's comments after they were made public.

"This statement represents presidential leadership on immigration that will allow us to solve a difficult problem," Graham said in a statement. "I truly appreciate President Trump making it clear that he supports a path to citizenship for DACA recipients. This will greatly help the Senate efforts to craft a proposal which President Trump can sign into law."

Sen. Dick Durbin, an Illinois Democrat, also appeared to praise his remarks in tweeting, "The President is headed in the right direction here" with a link to a story on Trump's comments.

Trump also once again equivocated on whether he might extend the deadline for DACA permits to begin expiring if Congress can't get ready in time — a possibility that if left open could complicate the sense of urgency in Congress to reach a deal.

"Yeah, I might do that," Trump said of moving the deadline, which is March 5. "I'm not guaranteeing it because I want to put a little bit of -- but I certainly have the right to do it."

The President's openness to a pathway to citizenship and clear articulation that the wall, family-based migration and diversity lottery were all he wanted in this deal could help Republicans pare down what conservatives have been pushing for.

"After DACA is done, we will look at the overall immigration," Trump said. "In the initial (deal), we're putting chain, a negotiated chain, we're putting a replacement for lottery or an end to lottery ... and we are going to build a wall, so those three primary things."

The wall

During the meeting with reporters, Trump also explained what he's looking for on his long-promised border wall, saying that "if you don't have a wall, you don't have DACA."

The President said he wanted $25 billion for the wall and $5 billion for "other security measures," all put in a trust fund. He also reiterated that the wall would be roughly 800 miles of new construction plus other replacement fencing and wall, and that it would not have to go anywhere natural barriers existed, like mountains and rivers.

"I'm going to build it way under budget, but we're putting down $25 billion for the wall," Trump said. "But we will build it way under."

Family immigration and diversity lottery

The President also offered some clarity on what he's looking for on his asks to curtail "chain migration," or family-based visa categories, and the diversity visa lottery — though he left some wiggle room for negotiation.

On chain migration, the President seemed to saw the only visa categories would be for spouses and minor children, but called parents a "tricky situation."

"You'll have wives and husbands and you'll have sons and daughters, and you'll talk about parents, the parents is a tricky situation because they came here illegally," Trump said.

He repeated his complaints about the diversity lottery — incorrectly suggesting that countries select nefarious characters for the randomly-selected immigrants that still go through vetting — but said it could be replaced or ended.

"It could be a replacement, we bring people in from various countries that come in based on merit and various other reasons," Trump said. "I think even the Democrats know the lottery system is not good. It's a bad system. By the way, great system for other countries, bad system for us."

The President's endorsement of a deal is seen as critical for passing it in Congress — especially in the House, where the Republican base has been pushing House Speaker Paul Ryan to secure the most conservative deal possible regardless of what can pass the Senate, where Democratic votes are required to clear a 60 vote threshold to advance legislation.

As Trump was leaving the impromptu gathering with reporters, he turned to Kelly and asked for a deal in a few days, prompting laughter from the room.

"Hey, chief, will you do me a favor? When we come back (from Davos), I want you to have a deal, OK? See if we can have a deal," Trump told his chief of staff.