Ukraine on Saturday was seriously considering a revised American proposal for its vast natural resources that contains virtually the same provisions that Kyiv previously rejected as too onerous, according to a draft document of the new proposal.

Some of the terms appear even tougher than in a previous draft.

Though Ukraine had not finalized the deal as of Saturday afternoon, its assent to the terms would represent a capitulation to American demands after a week of intense pressure from President Trump. The American president views access to Ukraine’s vast mineral wealth as necessary repayment for the billions the United States has provided Kyiv for its war against Russia.

The deal could strip Ukraine of funds that are now mostly invested in the country’s military and defense industry, and that could help rebuild the country once the war is over.

The terms of the new proposal, which is dated Feb. 21 and was reviewed by The New York Times, call for Ukraine to relinquish half of its revenues from natural resources, including minerals, gas and oil, as well as earnings from ports and other infrastructure.

A similar demand was made in a previous version of the deal, dated Feb. 14 and reviewed by The Times. Four current and former Ukrainian officials and a Ukrainian businessman who had the terms of the new proposal described to them confirmed that the demand remained unchanged.

Ukraine had been floating the prospect of a partnership with the United States on its valuable natural resources as a way to persuade Mr. Trump to provide additional support for its war effort as well as guarantees against future Russian aggression if a peace deal is struck.

The new document provides neither. In particular, President Volodymyr Zelensky had been seeking security guarantees for Ukraine, a condition that was absent in the first draft agreement presented to him last week, prompting him to decline to sign the deal.

The new document states that the revenues will be directed to a fund in which the United States holds 100 percent financial interest, and that Ukraine should contribute to the fund until it reaches $500 billion — the amount Mr. Trump has demanded from the war-torn country in exchange for American aid.

That sum, more than twice Ukraine’s economic output before the war, was not mentioned in the previous version of the deal. It is unclear whether Mr. Trump is requesting that sum in exchange for past American military and financial assistance, or whether it would also apply to future support.

The revised proposal states that the United States could reinvest a portion of the revenue into Ukraine’s postwar reconstruction, including by investing in the development of the country’s subsoil assets and infrastructure.

The new draft agreement also includes provisions for revenues from territories currently occupied by Russia, in the event they were freed: The share of resource revenues contributed to the fund from liberated areas would be 66 percent. Russia currently occupies about a fifth of Ukraine’s territory, including significant portions of the resource-rich Donbas region.

The deal could potentially be finalized before the end of the day on Saturday, but it could also be delayed, given Mr. Zelensky’s previous opposition to its terms.

Keith Kellogg, Mr. Trump’s special envoy to Ukraine and Russia, visited Kyiv from Wednesday to Friday and discussed the new proposal with Mr. Zelensky.

A potential deal for Ukraine’s resources has been a major point of dispute in a rapidly deteriorating relationship between Mr. Zelensky and Mr. Trump. Their interactions became acrimonious in the last week as the American president assailed Mr. Zelensky in highly personal terms, calling him “an unelected dictator.”

The Ukrainian president, in turn, said that Mr. Trump was living in a “disinformation web” after Mr. Trump falsely claimed that Ukraine had started the war against Russia.

Two of the people who had the new proposal described to them said that one of the few changes made by the United States that could satisfy Ukraine was the removal of a clause placing the deal under the jurisdiction of a New York court. The provision had raised concerns on the Ukrainian side, because it could weaken Ukraine’s legal standing in case of a dispute.

The United States has allocated $119 billion for aid to Ukraine, according to the Kiel Institute for the World Economy, a research organization in Germany.

The Trump administration has suggested that the mere presence of American economic interests in Ukraine would be a security guarantee for Kyiv. Top U.S. cabinet members have pressed Mr. Zelensky to sign the deal in recent days.

“President Zelensky is going to sign that deal, and you will see that in the very short term,” the U.S. national security adviser, Mike Waltz, said on Friday. “And that is good for Ukraine. What better could you have for Ukraine than to be in an economic partnership with the United States?”