U.S. Immigration and Customs Enforcement is considering a plan to significantly reduce its detention capacity after Republicans in Congress blocked a bill that would have given the agency more than $7 billion, officials said Wednesday.

To stay within the current budget, ICE would have to cut detention levels by more than 10,000 places within months, according to documents outlining the proposal obtained by The New York Times. The agency could either release some of the 38,000 people now in custody or refuse to fill vacant positions once the cases are resolved.

Three officials familiar with the plan said it is under active consideration within ICE. The officials spoke on condition of anonymity to discuss what they described as unforeseen events.

The proposal came first reported by The Washington Post.

The plan comes at a time of immigration crisis in the United States, with record numbers of people entering the country and the asylum system virtually broken. Bitter politics have paralyzed any movement on the issue as Republicans use the issue as a political weapon against President Biden.

Mr. Biden has implored Congress to pass bipartisan legislation that would have limited migration at the southern border. But his predecessor and likely challenger in this year's election, former President Donald J. Trump, pressured Republicans to block the deal, saying it would be a “gift” to Democrats.

In fact, many Republicans are now rejecting a deal they had previously called for, blocking the kinds of measures, such as stricter ICE enforcement, that they have sought for years.

ICE has said it faces a budget shortfall of hundreds of millions of dollars.

Rep. Mark E. Green of Tennessee, the Republican chairman of the House Homeland Security Committee, said Alejandro N. Mayorkas, the secretary of Homeland Security, was fully responsible for the problems at the border agency.

“Instead of treating enforcement like a hostage negotiation — 'give us more money or else' — Secretary Mayorkas should just do his job and follow the law,” Mr. Green said.

He spoke a day after House Republicans ousted Mr. Mayorkas over solid Democratic opposition. The charges against Mr. Mayorkas are expected to be dismissed in the Democratic-led Senate.

Democrats said the ICE shortage was a predictable result of Republican strategy.

“Republicans have been playing with fire for months by refusing to fund necessary border security operations and instead pursuing a sham impeachment,” said Rep. Bennie Thompson of Mississippi, the top Democrat on the Homeland Security Committee. He added that Republican lawmakers' stance was “all because Donald Trump wants a political wedge issue to remain in an election year.”

In the past, the Homeland Security Department, which oversees ICE, has siphoned off money from other agencies to cover budget shortfalls. But more drastic steps have also been taken. In 2013, during the Obama administration, ICE released more than 2,000 detainees due to budget issues.

The latest ICE proposal said the agency should also reduce the number of migrants tracked using ankle monitors, which the Biden administration is using as an alternative to detention in some cases, especially for families with young children.

“The administration has repeatedly requested additional resources for DHS's vital missions at the southwest border, and Congress has chronically underfunded them,” Department of Homeland Security spokeswoman Erin Heeter said this week.

The United States and 21 other countries pledged Saturday at the United Nations Climate Summit in Dubai to triple nuclear power capacity by 2050, saying the revival of nuclear energy is crucial to cutting CO2 emissions to near to return zero.

Advocates of nuclear power, which provides 18 percent of electricity in the United States, say it is a clean, safe and reliable complement to wind and solar energy. But a major obstacle is financing. Last month, a developer of small nuclear reactors in Idaho said yes canceling a project which was expected to be part of a new wave of power plants. The cost of building the reactors had risen from $5.3 billion to $9.3 billion due to rising interest rates and inflation.

Britain, Canada, France, Ghana, South Korea, Sweden and the United Arab Emirates were among the 22 countries to do so signed the statement capacity to triple compared to 2020 levels.

John Kerry, President Biden’s climate envoy, said there were “trillions of dollars” available that could be used for nuclear energy investments. “We are not saying to anyone that this will absolutely be the far-reaching alternative to any other energy source – no, that is not what brings us here,” he said. But, he added, science has shown that “you can’t get to net zero by 2050 without nuclear power.”

President Emmanuel Macron of France said nuclear energy, including small modular reactors, is an “indispensable solution” for efforts to curb climate change. France is Europe’s largest producer of nuclear energy.

Mr. Macron and other leaders, including Prime Minister Ulf Kristersson of Sweden, called on the World Bank and international financial institutions to help finance nuclear projects. Mr Kristersson said governments “must take on a role in sharing the financial risks to strengthen conditions and provide additional incentives for nuclear energy investments.”

While world leaders on Saturday called nuclear energy the most effective alternative to fossil fuels, some climate activists were skeptical.

Masayoshi Iyoda, a Japan-based activist from 350.org, an international climate action campaign, quoted the nuclear disaster in Fukushima in 2011, saying nuclear power was a dangerous distraction from decarbonization goals. “It is simply too expensive, too risky, too undemocratic and too time-consuming,” he said in a statement.

“We already have cheaper, safer, democratic and faster solutions to the climate crisis, and that is renewable energy and energy efficiency,” Mr Iyoda said.