Through legal challenges, the tribes have blocked completion of a 75-mile road.

Delegates here from some poor countries are so unhappy with rich nations' efforts to help them that they are warning of a possible move to block completion of a global trade agreement.

Delta's aim is to block completion of a flood control dam around Leningrad.

India's new Government has not yet threatened to block completion of the accord, although some diplomats are worried that New Delhi's stand could harden in coming days.

Many officials say they doubt the United States will push hard to resolve the long dispute over farm subsidies that has blocked completion of talks to liberalize world trade.

Reid, who has long been an opponent of the centralized nuclear waste facility in his home state, said he would continue to work to block completion of the project.

Mr. King refused to disclose the issues that had blocked completion of the deal.

Contending that the United States and Pakistan had blocked completion of an agreement to end the eight-year war, the Government said its withdrawal would be delayed as long as the talks remain stalled.

But the impasse over farm subsidies blocked completion.

Reid has said that he would continue to work to block completion of the project, and is quoted as having said: "Yucca Mountain is dead.