White House chief of staff Mark Meadows said Thursday that President Trump is preparing "aggressive" executive action on coronavirus stimulus if the sides fail to solidify a deal on emergency legislation in the coming days.

Heading in to yet another closed-door meeting with top Democratic leaders in the Capitol, Meadows said he hopes the parties can iron out their differences and preempt such a unilateral action by the White House. But he also warned that those differences remain substantial, not least the more than trillion-dollar gap in the overall size of the latest coronavirus aid package.

"At some point you have to understand that they’re not willing to make a deal. And that’s why the president is prepared to take executive action," Meadows told reporters just outside the office of Speaker Nancy Pelosi (D-Calif.).

"Certainly there are limitations with what we can do from an executive order point of view," he added, "but we will be as aggressive and as robust as we possibly can be as we deal with trying to meet the needs."

The comments arrive as the parties seem to be at a standstill in their high-stakes negotiations over the fifth round of emergency coronavirus relief in as many months.

House Democrats had passed a $3.4 trillion package in May, including funding for subsidized unemployment benefits, coronavirus testing, state and local governments and the U.S. Postal Service.

Senate Republicans countered with a $1.1 trillion package, featuring a direct payment for individuals and families; $105 billion to help schools reopen safely; and new funding to help small businesses weather the pandemic. The GOP bill also includes an extension of unemployment benefits, but it's less generous than the Democrats' plan. And there is no money for the Postal Service or state and local governments.

All of those areas remain significant barriers heading into Thursday's meeting between Pelosi, Meadows, Senate Minority Leader Charles Schumer (D-N.Y.) and Treasury Secretary Steven Mnuchin.

Absent a deal, Trump has floated the notion of acting unilaterally to expand unemployment benefits, help renters by extending a moratorium on evictions, and put more money in workers' pockets with a payroll tax cut.

Meadows did not provide details of the plan, nor did he attach a timeline to it. He put the onus on Pelosi and Schumer to preclude the need for executive action by giving ground on some of their demands.

"Assuming that we made great progress tonight I would hope that would buy us some time," Meadows said. "Again, it really depends on — not on us — it really depends more on the Democrats and their willingness to either make a deal and show that they're willing to compromise.

"We haven't seen that to date."

Yet Republican leaders are in a difficult position to make massive demands, since the Senate GOP conference is sharply divided over how — and even whether — Congress should intervene this month to prop up a health care system under heavy strain from the coronavirus, and an economy that's been devastated by it.

Earlier in the day, Pelosi and Schumer had both noted that Senate Republicans couldn't muster 51 votes to pass their own $1.1 trillion package through the upper chamber, let alone the 60 votes needed to elude a Democratic filibuster.

Asked about Trump's vow to adopt new stimulus by executive actions, Pelosi was dismissive.

"I don't think they know what they're talking about," she said.