President Bush's nominee to become the next U.S. Ambassador to the United Nations, John Danforth, has testified before a U.S. Senate panel ahead of his expected Senate confirmation.

Mr. Danforth was serving as President Bush's special envoy to Sudan when he was nominated to represent the United States at the United Nations.

He is well-known in the Senate, where he served for nearly two decades as a Republican Senator from Missouri before he retired in 1995.

He received a warm welcome before the Senate Foreign Relations Committee Thursday. Chairman Richard Lugar, an Indiana Republican, said Mr. Danforth is the right man for the job at an especially critical time.

"American credibility in the world, progress in the war on terrorism and our relations to other allies will be greatly affected by what can be achieved at the U.N. in the coming years. Senator Danforth is eminently qualified to meet those and other challenges. We recognize his deep personal commitment necessary to undertake this difficult assignment," he said.

Mr. Danforth acknowledged that the challenges awaiting him, if confirmed, are daunting, particularly those relating to the war on terrorism. "I do not know if anybody knows how to deal with this problem," he said. "I don't. But I do have this sense that we better get our act together, and by "we", I mean the international community."

The top Democrat on the committee, Senator Joe Biden of Delaware, sought to warn Mr. Danforth about unnamed Bush administration officials whom he said have unilateralist leanings. "You will, unless something has drastically changed, run into honorable, decent, intelligent forces within the administration who have no regard for the U.N.," he said.

But Mr. Danforth said he had a recent phone conversation with Mr. Bush during which the President emphasized that he thought the U.N. Ambassador's position is an important one, and that the war on terrorism cannot be won without the United Nations.

During his appearance before the committee, Mr. Danforth was asked about a number of global trouble spots, including the violence in Sudan's western Darfur region. "It is an absolutely intolerable situation. It cannot be permitted to continue to exist," he said.

Mr. Danforth said he expects a U.N. resolution on the issue soon. He said the world body may consider a peacekeeping force in the region, or even impose sanctions on Khartoum.

On other issues, he vowed to promote efforts to resolve the Israeli-Palestinian conflict and to seek greater U.N. involvement in Iraq.

Senate confirmation is expected in the coming weeks. Mr. Danforth would succeed John Negroponte, who is now Ambassador to Iraq.