A vote to advance the massive coronavirus stimulus bill failed on Sunday night in the Senate as negotiations had yet to produce a deal on the more than $1 trillion aid package. A second vote has now been scheduled for Monday shortly after 12:00 p.m. ET.

Republicans, who needed 60 votes to move forward on the bill, weren't able to win over any Democrats to proceed, meaning no aid will flow to the economy — including checks to individuals, help for small businesses and bailouts for big corporations — until an agreement is reached.

Democrats said that they were dissatisfied with worker protections in the bill, which was written by Republicans, and that the rules on corporate bailouts are too lax.

"We'll see what happens. I think we'll get there," President Donald Trump said at the White House moments after the measure failed to advance. "We have to help the worker. We have to save the companies."

"All of a sudden, the Democratic leader [Chuck Schumer, D-N.Y.] and the speaker of the House [Nancy Pelosi, D-Calif.] shows up and we're back to square one," McConnell said, blaming Democrats for "obstruction."

"So we're fiddling here, fiddling with the emotions of the American people, fiddling with the markets, fiddling with our health care. The American people expect us to act tomorrow," McConnell said. "And I want everybody to fully understand if we aren't able to act [Monday], it'll be because of our colleagues on the other side continuing to dicker when the country expects us to come together and address this problem."

McConnell said the second vote, set for Monday, would show whether there's been any "change of heart" among the Democrats and he noted it would take after the markets open, which could increase pressure on Democrats not to oppose the measure and frighten investors.

Schumer is scheduled to meet with Treasury Secretary Mnuchin at 9 a.m. ET on Monday to continue talks.

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Schumer said: "Early this morning (Sunday), Leader McConnell presented to us a highly partisan bill written exclusively by Republicans, and he said he would call a vote to proceed to it today. So who is being partisan? He knows darn well for this bill to pass it needs both Democratic and Republican support.

"Given more time, I believe we could reach a point where the legislation is close enough to what the nation needs for all senators, all senators to want to move forward," Schumer added. "We are not yet at that point."

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The stalemate unfolded after top Democrats said Sunday that they're not yet ready to sign off on the major coronavirus stimulus package — and will be preparing their own legislation — as Congress tries to ready the bill for passage as soon as Monday.

Just before an 11 a.m. meeting of the top Republican and Democratic congressional leaders, as well as Treasury Secretary Steven Mnuchin, Pelosi told reporters that "from my standpoint, we are apart."

Schumer told reporters ahead of the meeting that "we need a bill that puts workers first, not corporations," and declined to say whether he supports the current bill.

Leaving Sunday's meeting, Pelosi said that she will introduce her own legislative package but that "we are still talking" with Republican leaders. She said that at this point, however, there is no bipartisan deal.

The meeting came hours before the critical procedural vote on the Phase III bill, the text of which hasn't yet been released. McConnell had delayed the vote from 3 p.m. to 6 p.m. ET to give congressional leaders more time to hammer out the details.

Just before Sunday morning's meeting, Democrats revealed what they are still opposed to in the stimulus package. According to a person familiar with the negotiations, Democrats say the language would allow for corporations to keep bailout money while still firing workers, that the bailout money would have virtually no restraints and that there are very weak stock buyback restrictions.

A senior Democratic aide told NBC News that Democrats are concerned that the bill lacks specific provisions to protect people from evictions, foreclosure or forbearance and that it would allow for only three months of unemployment insurance.

McConnell told reporters after the meeting that the Senate plans to move forward with its bill and is "hopeful and optimistic" that it will have bipartisan support.

"But make no mistake about it, we'll be voting tomorrow. I mean, the wheel has to stop at some point," McConnell said. "And I don't want any of you to buy the notion that this isn't a thoroughly bipartisan proposal already. There's still some elbowing and maneuvering for room, as you can imagine, but this is a pretty solid-like bipartisan proposal agreed to by a lot of rank-and-file Democrats who were involved in drafting it."

House Minority Leader Kevin McCarthy, R-Calif., said that he thought the meeting "was very productive" and that both sides are "very close" to a deal. He added that he doesn't think Pelosi's introducing her own legislation would be "productive."

"I don't know that we'd have the time for that," he said, adding he believes it "would do the country a lot of damage."

Mnuchin told reporters he's still optimistic about a deal, saying, "We still think we have an overall understanding, and we're going to try to get this on paper."

One potential complication was the news Sunday that Sen. Rand Paul, R-Ky., has tested positive for the coronavirus. Paul in recent days had contact with many other senators, and his announcement triggered a discussion about whether senators should immediately return home or self-quarantine. Sens. Mike Lee and Mitt Romney, both Utah Republicans, said later Sunday that they would be self-quarantining for two weeks and would have to miss floor votes after having had "extended" interactions with Paul.

Sen. Bill Cassidy, R-La., said he is concerned that other senators could be infected.

"I am concerned about every American. This thing is incredibly infectious, so I am concerned about every American," he said. "Now senators, as a rule, tend to be a little bit older, so senators are at an increased risk for complications. But, by the way, not as high risk as a nursing home. And so we just need to be concerned about everybody right now."

Democratic senators learned of Paul's coronavirus test while they were in their Democratic caucus meeting Sunday, according to two sources with direct knowledge of the meeting. About half the senators were in the room, with the rest calling in by conference call. Once the Paul news came out, the senators on the phone urged those in the room to leave immediately and to stop congregating in the room.

But other senators pointed out that there's no provision for the Senate to vote unless senators are physically present and that they can't just all go home.

According to details of the bill released Thursday, Senate Republicans propose to give a $1,200 check to every American adult with an income under $75,000, decreasing gradually after that and zeroing out at $99,000 income. Checks would fall to $600 for those with little or no income tax liability, and $500 would be added in per child. The eligibility would be based on 2018 tax filings.

Meanwhile, Sen. Bernie Sanders, I-Vt., has proposed universal $2,000 checks per month "for the duration of the crisis." Other Senate Democrats have suggested quarterly checks that begin at $2,000 per person, decreasing over time based on economic triggers.

The total coronavirus package McConnell released would cost about $1 trillion. Already, Congress has approved — and Trump has signed — coronavirus aid legislation that provides free coronavirus testing and ensures paid emergency leave, among other measures.