© Reuters. FILE PHOTO: A combination photo of House Minority Leader Nancy Pelosi President Donald Trump and Senate Minority Leader Chuck Schumer

By Ayesha Rascoe and Richard Cowan

WASHINGTON (Reuters) - President Donald Trump said on Thursday he was close to a deal with Democratic congressional leaders on protections for illegal immigrants brought to the United States as children, astounding fellow Republicans again while alarming conservative supporters.

Trump said any final agreement must include border security measures including surveillance systems but would not include funding for his planned wall along the U.S.-Mexican border, a central 2016 campaign promise. Trump said the wall would "come later" and warned Democrats not to obstruct it.

Trump described the parameters of an agreement on the fate of the roughly 800,000 so-called Dreamers reached in his White House meeting on Wednesday evening with top Senate Democrat Chuck Schumer and top House of Representatives Democrat Nancy Pelosi.

"We have to have an understanding that, whether it's in the budget or some other vehicle, in a very short period of time the wall will be funded. Otherwise, we're not doing anything," Trump said after landing in Florida to survey hurricane damage.

Schumer and Pelosi reiterated their opposition to the wall, and Democrats in the past have promised to block funding for it.

"I think we're fairly close but we have to get massive border security," Trump told reporters earlier in the day of a potential deal.

Trump said Republican House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell were both "on board" with the potential deal and that "we're doing it in conjunction with the Republicans." Trump spoke with Ryan and McConnell on Thursday morning only after he had reached the outline of the deal with the Democrats.

The potential agreement was the latest development in the president's newfound willingness to work with Democrats after Republicans, who control Congress, failed to deliver legislative victories on healthcare and other matters.

Trump stunned Republican leaders last week by reaching an agreement with Schumer and Pelosi to fund the government and raise the U.S. debt ceiling through mid-December.

The president defended his outreach to the opposition party, saying if Republicans did not stick together, "then I'm going to have to get a little bit of help from the Democrats."

"We have to get things passed," Trump told reporters aboard Air Force One.

Trump rescinded the Deferred Action for Childhood Arrivals (DACA) program earlier this month but made that effective in March, giving lawmakers six months to come up with an alternative for the Dreamers. DACA, created by Trump's Democratic predecessor, Barack Obama, shields the Dreamers, mostly Hispanic young adults, from deportation and provides work permits.

Pelosi pointed to a bill offered by Republican House Homeland Security Committee Chairman Michael McCaul as a possible basis for a deal with Trump on border security.

It calls for more money for high-tech surveillance equipment, stronger measures at U.S. ports of entry, more Border Patrol and customs agents and letting National Guard personnel help with aviation and intelligence support on the U.S.-Mexico border.

CITIZENSHIP ISSUE

Trump said that "we're not looking at citizenship" for the Dreamers, a comment that differed with how Pelosi and Schumer described their understanding with the president.

They told reporters Trump had embraced the provisions of a bipartisan proposal called the Dream Act that would grant permanent legal resident status to Dreamers who qualify, allowing them to attend college, work and serve in the U.S. military without fear of deportation. It also would provide a pathway to U.S. citizenship after at least eight years.

Before Trump made his comment on citizenship, a White House spokeswoman, Lindsay Walters, told reporters traveling with him to Florida that the administration would discuss "a responsible path forward" that could include "legal citizenship over a period of time."

McConnell and Ryan, both of whom have had a tense relationship with Trump, made comments that suggested they might not be on board, as the president said.

"There is no agreement," Ryan told reporters about DACA.

"I think the president understands that he's got to work the congressional majority," he told reporters, referring to Republicans, adding that "we have not begun negotiations," although he expected a compromise to be reached.

McConnell issued a noncommittal statement.

"As Congress debates the best ways to address illegal immigration through strong border security and interior enforcement, DACA should be part of those discussions. We look forward to receiving the Trump administration's legislative proposal as we continue our work on these issues," he said.

CONSERVATIVE BACKLASH

Trump faced a quick backlash from his hard-line conservative political base over his potential deal on DACA.

He had promised as a candidate to deport all of the estimated 11 million illegal immigrants in the United States, and said a border wall would be built, paid for by Mexico, to stop the flow of illegal immigrants and drugs. Mexico has said it will not pay for the structure.

"It looks to me like he's preparing to keep Hillary Clinton's campaign promise rather than his own," Republican Representative Steve King told CNN, referring to Trump's Democratic election rival.

Breitbart News, the hard-line conservative news website headed by Trump's former top strategist, Steve Bannon, called the president "Amnesty Don" in a headline. Many conservatives oppose giving legal status or a path toward citizenship to illegal immigrants, calling such steps "amnesty" to lawbreakers. Trump said on Thursday he did not support amnesty.

Conservative pundit Ann Coulter wrote on Twitter: "At this point, who DOESN'T want Trump impeached?"