London ? Backed by the United States, Britain pressed the world’s economic powerhouses Friday to cancel $15 billion owed by 18 poor nations and free up money to spend on health care, education and infrastructure in those struggling lands.

There was support for the plan at talks among finance ministers from the Group of Eight nations, but some reported differences on how to the finance the loan write-offs and said an agreement was unlikely before next month’s meeting of G-8 leaders in Scotland.

Britain and the United States want their G-8 partners to support eventually canceling 100 percent of all debts that poor countries owe multilateral institutions such as the World Bank, the International Monetary Fund and the African Development Bank.

The proposal, negotiated earlier this week in Washington by Prime Minister Tony Blair and President Bush, followed a significant concession from the White House that money used to reimburse the lending institutions would not come out of future aid, British officials said.

The agreement initially would cover 18 nations eligible for debt relief under an IMF-World Bank program to encourage economic and government reforms. Aid experts estimate that would leave those countries with an extra $1 billion to spend at home each year.