Washington (CNN) President Donald Trump emerged into the frigid air on Monday after a snowy weekend spent indoors and unleashed on the FBI and Democrats after a slew of new reporting on his relationship with Russia .

He angrily denied ever working for Moscow, his first definitive rebuttal of acting on Russia's behalf that came after a non-denial over the weekend . And he demanded Democrats return to the negotiating table to end a partial government shutdown, though did not offer new incentives after talks crumbled last week.

For Trump, it was an extension of a weekend spent tweeting from his third-floor White House residence, where he's mostly remained throughout the shutdown, much to his own self-regard.

"I've been here all weekend," he declared as he stepped onto the White House South Lawn before departing for New Orleans, where he was to address the American Farm Bureau.

Responding to a report the FBI opened an investigation into whether he acted for Russia against US interests, Trump was indignant.

"I never worked for Russia, and you know that answer better than anybody," Trump said, calling the entire investigation into possible collusion between his campaign and Moscow "a whole big fat hoax."

Trump, in a combative mood, derided the FBI officials who launched the probe as "known scoundrels" and "dirty cops." And he again heralded his decision to fire FBI Director James Comey, despite the ramifications that move has had to the special counsel's investigation.

Under siege and on the attack

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Trump had spent much of his weekend making similar attacks on Twitter. He insisted he's been tougher on Russia than any of his predecessors, and attacked the FBI for failing to investigate his 2016 rival Hillary Clinton.

Amid the partial government shutdown, Trump has been confined mainly to the White House, believing weekend trips to his Florida estate would appear insensitive. He's lambasted Democrats for leaving town and failing to negotiate on his border wall.

On Monday, he claimed some Democrats were ready to deal, though didn't offer names.

"Many of them are calling and many of them are breaking," he said. "The Republicans are rock solid. We've got to take care of our border."

Still, he said he'd rejected a plan offered by a top ally, Sen. Lindsey Graham of South Carolina, to reopen the government before restarting immigration talks, saying "I'm not interested."

And he backed off the prospects of using a national emergency declaration to secure border wall funds, an option that could have paved the way to opened shuttered agencies.

That left even him wondering how an agreement could be struck that would allow 800,000 federal workers to again receive their paychecks.

"I don't know if we're close to a deal," he said. "It should be the easiest deal that I've ever seen."

Trump is digging his heels on his demand for a border wall as the shutdown enters its fourth week, people familiar with the matter say, telling aides and allies that he believes he is winning the battle for public support.

Over the last 24 hours, Trump has privately touted a Washington Post-ABC News poll indicating that public support for a border wall has increased to 42% from 34% last year, a source familiar with his comments told CNN.

Still, other polling shows most Americans place the blame for the shutdown on the President. a CNN/SSRS survey published Sunday shows a majority of the public blames the President, with 55% saying he is more responsible for the shutdown than are Democrats in Congress, while 32% say the blame rests mostly with the Democrats.

Working the phones -- with allies

The shutdown was one topic of many that Trump discussed on the phone over the weekend with advisers and allies. On Saturday, he made an afternoon decision to phone into the Fox News television program of his personal friend Jeanine Pirro, who questioned him about the FBI's investigation.

When she asked whether he worked for Russia, he didn't offer a direct answer.

"I think it's the most insulting thing I've ever been asked," Trump said. "I think it's the most insulting article I've ever had written, and if you read the article you'll see that they found absolutely nothing."

The non-denial confounded many of Trump's supporters and aides, though Trump later told advisers he believed his answer had been forceful enough.

On Monday, however, he answered more explicitly and with renewed umbrage at the FBI's actions.

"The people doing that investigation were people that have been caught that are known scoundrels," he said. "I guess you could say they're dirty cops."

He used familiar attack lines against FBI officials, and said the agency had experienced a turnaround on morale after those officials' departures.

Pressed about another weekend report -- this one from The Washington Post -- that he sought to keep secret the details of his meetings with Russian President Vladimir Putin, Trump claimed ignorance.

"I just don't know anything about it," he said, before insisting that one-on-one meetings with foreign leaders were routine and not nefarious.

"We have those meetings all the time," Trump said. "No big deal."

Earlier, Trump's senior counselor Kellyanne Conway did not deny the President took steps to keep the details of his meetings with Putin private.

"The President at that time, in 2017, was suffering from a great number of leaks," she said. "We were very concerned about, we're always concerned about leaks obviously, particularly national security leaks."

On the horizon

Trump's icy morning remarks ended as he departed for Louisiana to speak to farmers, a group he's boasted about helping. Earlier in the day, he mistakenly wrote on Twitter he was traveling to Nashville, a message he later deleted.

When Trump returns again to the White House, he will host the Clemson Tigers football team, this year's national champions. But with much of his residence staff furloughed and nearly a foot of snow closing the rest of the government, the President suggested the catering might be altered.

"I think we're going to serve McDonald's, Wendy's and Burger King's with some pizza," he said. "I really mean it. It will be interesting. I would think that's their favorite food."