WASHINGTON (Reuters) - President Donald Trump and Democratic leaders agreed on Tuesday to spend $2 trillion on U.S. roads, bridges, power grids, water and broadband infrastructure, while leaving the thorny details of how to pay for it all to another meeting in three weeks.

The two sides met at the White House and described their discussion in positive terms, but the air of bipartisan cooperation may not last long.

Republicans are not willing to roll back tax cuts from Trump’s 2017 tax reform legislation, an idea Democrats who largely opposed that measure have floated as a way of financing the infrastructure plans.

Trump has not decided whether he would support an increase in fuel taxes to fund infrastructure projects, according to his top economic adviser, Larry Kudlow.

Still, the meeting between Trump, House of Representatives Speaker Nancy Pelosi and Senate Democratic leader Chuck Schumer contrasted with previous, more heated discussions on immigration and border security.

“We just had a very productive meeting with the president of the United States,” Pelosi told reporters at the White House after it concluded. “We did come to one agreement: That the agreement would be big and bold.”

Schumer said Trump was eager to have a meaty number on the bill.

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“We agreed on a number, which was very, very good - $2 trillion for infrastructure. Originally we had started with a lower - even the president was eager to push it up to $2 trillion,” Schumer said.

The White House called the meeting “excellent and productive” and said another one would take place in three weeks.

“The United States has not come even close to properly investing in infrastructure for many years, foolishly prioritizing the interests of other countries over our own,” White House spokeswoman Sarah Sanders said in a statement.

“The president looks forward to working together in a bipartisan way and getting things done for the American people.”

Still, Trump’s chief of staff Mick Mulvaney said an agreement was unlikely because Democrats would not back environment deregulation, which the White House would want to speed up construction.

“I think there is a much better chance of getting the USMCA passed than getting the infrastructure bill passed,” Mulvaney said, referring to the new trade deal with Canada and Mexico, at the Milken Institute Global Conference in Beverly Hills.

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“I am all for more infrastructure. They could agree to $18 trillion – the question is how to pay for it,” said Republican Senator John Kennedy, who opposes borrowing more money or raising taxes to fund the proposals.

CLASHES

Trump has had a combative relationship with his Democratic congressional counterparts. An Oval Office meeting with Pelosi and Schumer in December included a long, open clash, played out in front of reporters and television cameras.

More recently, the president has criticized Democrats for pursuing investigations of his conduct after the release earlier this month of the redacted report by Special Counsel Robert Mueller on Russia’s intervention in the 2016 U.S. election.

That investigation did not establish that Trump’s campaign cooperated with Russia to influence the election, but it did not take a position on whether the president obstructed justice as the probe took place.

Democrats, who control the House of Representatives, are initiating further probes of Trump, but the Democratic leaders said that topic did not come up during the meeting.

“In previous meetings, the president has said, ‘If these investigations continue, I can’t work with you.’ He didn’t bring it up. And so, I believe we can do both at once,” Schumer said.

“We can come up with some good ideas on infrastructure. We want to hear his ideas on funding. That’s going to be the crucial point, in my opinion. And the House and the Senate can proceed in its oversight responsibilities. The two are not mutually exclusive and we were glad he didn’t make it that way.”

Trump wants to speed up permit approvals to boost construction projects as part of any infrastructure plan, White House adviser Kellyanne Conway said earlier on Tuesday. She warned Democrats not to try to include their ideas on combating climate change in any legislation.

A Democratic source familiar with the meeting described a smooth rapport between the leaders at the meeting, which was also attended by other Democratic lawmakers. The president shared some Tic Tac mints with Pelosi, the source said.

At one point Pelosi sought to get the attention of Trump and Schumer while they were having a side conversation.

“If I may have your attention … Mr. President … Chuck … Kids …,” she said, according to the source.