While relief operations after last week's devastating Indian Ocean tsunami are making "phenomenal progress" in areas that can be reached, "enormous problems" still persist in Indonesia, the United Nations humanitarian chief said on Thursday.

"We are doing an enormous job already, we already have hundreds of people working," Under-Secretary-General Jan Egeland told a news briefing in New York of the overall UN role as coordinator ofthe massive international relief effort.

"But we need to build up more, and we can and we will build up more, and dramatically so in the next few days."

He said local and national authorities must clamp down on the as yet few cases of "totally horrendous attempts" to traffic in child survivors of the disaster to prevent it becoming a "big problem."

Turning to the Indonesian provinces of Aceh and Sumatra, the region most ravaged by the tsunami, he said: "Big progress is being made by the day, we are reaching many more people today thanwe did yesterday, we are reaching them also with many more services in terms of water, food, shelter, health care."

"But we are having enormous problems still, and these problems will remain. This is the road-less, this is the communications-less part of the areas affected."

The remoteness and lack of infrastructure has impeded speedy access there to the relief operations that moved into top gear in other devastated zones of the dozen countries affected, such as Sri Lanka, India, Thailand, the Maldives and Somalia.

There, either the national authorities or the international community made "phenomenal progress" in covering the basic needs of the millions of victims, he said.

Regarding the toll in Aceh and Sumatra, Egeland said he did notthink "we are even close to having any figures of how many people died, how many people are missing and how many people are severelyaffected."

Estimates of the tsunami's overall toll put the death toll at 150,000, with nearly 100,000 of them so far in Indonesia. More than half a million people are believed to have been injured and up to 5 millions are classified as lacking basic services.

Egeland also reiterated his appeal to the global community not to forget the many other humanitarian crises in the world. "As thesituation evolves, I'm getting increasingly satisfied with how theworld is responding to the tsunami victims and I'm getting increasingly nervous for all the forgotten and neglected emergencies."

He said that perhaps the worst situation was in the Democratic Republic of the Congo where, outside the tsunami area, most people now die "from neglect and lack of attention and lack of presence" of the international community.

"There are as many nameless victims in the eastern Congo and inDarfur in western Sudan in a year as there may be in the tsunami-stricken societies," he added. "And I hope the world will be equally compassionate with those defenseless victims."