The United States threatened Thursday to use its Security Council veto if necessary to bar Boutros Boutros-Ghali from a second term as secretary-general of the United Nations.

"I hope they will change their minds," Boutros-Ghali told reporters in Bonn on Thursday before meeting President Roman Herzog of Germany, which like fellow European ally France has voiced strong support for the secretary-general.In Washington, White House spokesman Mike McCurry, asked about a second five-year term for the Egyptian diplomat, said: "There is no possibility of that."

Does that mean the United States will use its veto?

"Yes," McCurry said.

At the United Nations, Boutros-Ghali announced his intention Wednesday to run again. "The secretary-general has decided to run for a second term," U.N. spokesman Ahmad Fawzi announced. "Bou-tros-Ghali has taken this decision in view of the strong encouragement he has received from mem-ber states."

The decision to oppose Boutros-Ghali pits the Clinton administration against stalwart opposition in the United Nations, likely including three of the five powers with Security Council vetoes. In addition to France, China and Russia probably would vote for Boutros-Ghali. The fifth veto belongs to Britain, which has been silent on the matter.

"After careful consideration, President Clinton and the secretary of state have decided new leadership is needed in the United Nations," said State Department spokesman Nicholas Burns. "Based on that assessment, the United States will not support an extension of his term as secretary-general."

"We respect him as a distinguished international public servant, and we wish him well," Burns said. "We think the time has come for a new leader."

He said Secretary of State Warren Christopher had conveyed the decision to Boutros-Ghali. In Bonn, German Foreign Minister Klaus Kinkel said the visiting secretary-general gave him the impression that "announcement of the Americans' rejection of a second candidacy" spurred him into making public his intention to run.

Administration spokesmen characterized the decision as strictly a move to bring better management to the world organization.

"We need, all of us internationally, to identify someone capable of reforming the U.N. bureaucracy, increasing its cost effectiveness, reducing the budget and streamlining the organization," Burns said.

But Washington has been at odds with Boutros-Ghali over peacekeeping policies in Somalia and Bosnia, as well as over what administration officials and several members of Congress consider inadequate spending cuts.

Additionally, the United Nations and America's relationship with it have brought strong criticism from conservatives in the Republican party, especially the idea of putting U.S. peacekeeping troops under U.N. command. The question even threatens to become an issue in the presidential campaign.

Sen. Jesse Helms, R-N.C., chairman of the Senate Foreign Relations Committee, and a number of Republicans and Democrats have been vocal in insisting the United Nations needs an overhaul and Boutros-Ghali has not done enough to trim waste.

U.N. spokesman Fawzi did not say which countries are backing Boutros-Ghali, 73, who was elected in 1991.

The State Department's Burns said the search is on for a successor and that the United States had no candidate.

Among those being mentioned are three women: Irish President Mary Robinson, Prime Minister Gro Harlem Brundtland of Norway and Sadako Ogata, U.N. high commissioner for refugees.