Defying the administration, the Republican-led House on Thursday took up legislation that drastically would limit the U.S. financial commitment to the United Nations (search) because of anger about its conduct.

The U.S. would withhold half of its due if the organization failed to carry out specific changes, according to the proposal sponsored by GOP Rep. Henry Hyde (search) of Illinois, chairman of the House International Relations Committee.

The bill would withdraw U.S. support for future peacekeeping missions unless the United Nations overhauled its operations.

The House was expected to vote Friday on whether to pass Hyde's bill or an alternative from Rep. Tom Lantos of California, the committee's top Democrat.

Lantos' plan also would demand U.N. reforms, but allow the secretary of state to decide whether cuts in U.S. contributions were warranted.

The Bush administration says the automatic cut in dues payments would undermine U.S. credibility at the United Nations.

But administration officials did not say that Bush would threaten to veto Hyde's bill and they expressed support for compelling the United Nations to deal with its problems of waste and corruption.

Also Thursday, the administration supported a measured expansion of the Security Council, but said widespread reform of the United Nations takes precedence.

"We are not prepared to have Security Council reform sprint out ahead of the other extremely important reforms that have to take place," Secretary of State Condoleezza Rice said at a news conference. She cited management, peace-building and halting the proliferation of dangerous weapons technology.

Hyde's bill face an uncertain fate in the Senate. In addition, eight former U.S. ambassadors to the United Nations told lawmakers in a letter this week that withholding of dues would "create resentment, build animosity and actually strengthen opponents of reform."

The legislation, however, is a clear sign of congressional displeasure over the U.N.'s bureaucracy, its perceived anti-Americanism on many issues and recent scandals involving the oil-for-food program in Iraq (search) and the sexual misconduct of U.N. peacekeepers.

The bill lists 39 reforms sought. They include cutting the public information budget by 20 percent, establishing an independent oversight board and an ethics office, and denying countries that violate human rights from serving on human rights commissions.

The secretary of state would have to certify that 32 of the 39 reforms have been met by September 2007, and all 39 by the next year, to avoid a withdrawal of 50 percent of assessed dues.

U.S. assessed dues account for about 22 percent of the U.N.'s $2 billion annual general budget.

The financial penalties would not apply to the U.N.'s voluntarily funded programs, which include UNICEF and the U.N. High Commissioner for Refugees.