Republicans unveiled a $568 billion counterproposal to President Joe Biden's infrastructure plan on Thursday. The Republican plan —roughly a quarter of Biden's proposal — is more focused on physical infrastructure like the nation's roads, railways and bridges.

The package includes:

• $299 billion for roads and bridges

• $61 billion for public transit systems

• $20 billion for rail

• $13 billion for safety measures

• $17 billion for ports and inland waterways

• $44 billion for airports

• $65 billion for broadband

• $14 billion for water storage

Sen. Shelley Moore Capito (R., W. Va.), Sen. Roger Wicker (R., Miss.), Sen. Pat Toomey (R., Pa.) and Sen. John Barrasso (R., Wyo.) introduced the plan.

Capito said it's "critical" that the plan is paid for — but the proposal does not include specifics about how to do that. The senators suggested "some kind of user fee mechanisms" and repurposing unused COVID-19 relief funding.

Republicans have largely rejected Biden's $2 trillion infrastructure plan, saying it's too expensive and includes too many measures unrelated to physical infrastructure. They are also fiercely opposed to raising the corporate tax rate to 28% in order to pay for it, as Biden would like to do.

The Republican senators said on Thursday they want to keep the 2017 tax cuts — which reduced the corporate tax rate from 35% to 21% — in place.

Democratic lawmakers had already dismissed the counteroffer before it was even unveiled, saying it's not nearly enough. After the announcement, Senate Finance Committee Chairman Ron Wyden (D., Oreg.) told reporters corporations should help pay for an infrastructure plan.

"You're going to argue that those big corporations shouldn't pay a penny for infrastructure? Petty hard to get to a bipartisan approach from that," said Wyden. "I always try to find common ground, but that's going to be a stretch."

Wicker called the proposal a "serious effort to get negotiations started" with Democrats.

"This is a big proposal," said Wicker. "$568 billion is a very, very generous offer in dealing with infrastructure. It will get us a long way to where we want to go."

White House Press Secretary Jen Psaki said the administration sees the proposal as a starting point, and she expects a full briefing on the plan and staff-level discussions in the coming days. Psaki said the president would likely invite lawmakers to the White House sometime after his address to a joint session of Congress next week.

"The president has said from the beginning that he would welcome any good faith effort to find common ground, because the only unacceptable step would be inaction," said Psaki.

Biden has met with Republican and Democratic lawmakers at the White House to discuss ideas for an infrastructure package in recent weeks. Biden has said he'd like the proposal to be bipartisan and he's willing to compromise — but the two parties have yet to agree on what should be included in the package or how to pay for it.

The U.S. Chamber of Commerce said it was encouraged to see efforts to help move negotiations forward.

"For anyone who sincerely wants to see a bold and responsible infrastructure plan finally enacted into law, there is only one path forward: bipartisan negotiations," said Neil Bradley, Executive Vice President and Chief Policy Officer, U.S. Chamber of Commerce. "Whether Republican or Democrat – those who declare negotiations as futile before they have even begun are the ones standing in the way of long-overdue investments in our nation’s infrastructure."

Jessica Smith is chief political correspondent for Yahoo Finance, based in Washington, D.C. Follow her on Twitter at @JessicaASmith8.

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