The United Nations says international donors have committed $700 million for immediate aid to victims of the Indian Ocean tsunami. While funds flow in at an unprecedented pace, the goal of reaching all victims remains elusive.

U.N. emergency relief coordinator Jan Egeland is predicting that donors will meet or exceed the goal of nearly one billion dollars for immediate aid. After more than 80 contributing states met in Geneva, Mr. Egeland said this is the first time the world body has collected so much right after a disaster.

That optimism was tempered, however, by word that two and a half weeks after the tsunami struck, relief workers still have not reached large areas along Sumatra's northwest coast. Kevin Kennedy of the U.N. Office of Humanitarian Affairs says analysis through helicopter searches and satellite imagery indicates as many as 40 population centers may still be inaccessible by land.

"The road is washed out for hundreds of kilometers," he said. "The road no longer exists. It's gone. It's at sea, as a matter of fact. Where the ocean came in, and it came a distance of three miles at some points, the road is completely destroyed, so the road is just not there. One cannot build a road hundreds of kilometers long in the space of two weeks. It's just not possible. Particularly when our assets are focused on trying to get assistance out by air and other things to meet those needs."

Mr. Kennedy says air surveillance of the inland region to search for possible survivors has been incomplete because of the dense foliage. But he says newly-arrived helicopters will allow a better assessment within the next couple days.

"We have begun ?a more organized assessment of the needs along western coast of Sumatra, principally using helicopters from the United States, operating off ships off shore," he said. "That began today, and that's a combined operation,?and as we gather that data we'll have a better sense of who we're reaching and who we're not reaching."

Mr. Kennedy says aid is arriving rapidly at central points in northern Sumatra, such as Banda Aceh and Medan, for delivery outward. The Banda Aceh airport, for instance, handled an average of three flights a day before the tsunami struck. Now it handles 200 a day. Extra crews of air traffic controllers are being flown in to the area to handle the backlog of arriving cargo planes.

Officials estimate that governments and private individuals have pledged more than three billion dollars in short and long-term aid for the 12 countries hit by the tsunami.