GENEVA (AP) -- The United Nations released a new assessment of the 1986 Chernobyl nuclear meltdown Tuesday, saying the worst health consequences for millions of people may be yet to come.

"At least 100 times as much radiation was released by this accident as by the two atomic bombs dropped on Hiroshima and Nagasaki combined" at the end of World War II, said a 32-page booklet released to mark the 14th anniversary of the disaster.

Three people were killed in the explosion on April 26, 1986, and 28 emergency workers died within the first three months, the report said. It gave no other death toll, but noted that 106 of the other emergency workers that were first on the scene also were diagnosed with acute radiation syndrome.

And, the report said, a total of 600,000 emergency workers who helped in the cleanup and later built a cover to seal the destroyed reactor "must be constantly monitored for the effects of exposure to radiation."

The booklet, published by the U.N. Office for the Coordination of Humanitarian Affairs, said the three countries most affected by the radiation -- Belarus, Ukraine and Russia -- continue to pay the price.

"Chernobyl is a word we would all like to erase from our memory," said U.N. Secretary-General Kofi Annan in a foreword.

But, Annan added, "more than 7 million of our fellow human beings do not have the luxury of forgetting. They are still suffering, everyday, as a result of what happened." He said the exact number of victims may never be known, but that 3 million children require treatment and "many will die prematurely."

"Not until 2016, at the earliest, will be known the full number of those likely to develop serious medical conditions" because of delayed reactions to radiation exposure, he said.

Annan said response to a U.N. appeal launched three years ago had fallen so short that the original list of 60 projects had been shortened to the nine most urgent.

"These nine projects could, if implemented, make a vital difference to the lives of many people," Annan said in appealing for governments and institutions to contribute $9.5 million.

The projects include modernization of a hospital, creation of a network of centers to treat children and decontamination of schools, kindergartens and hospitals in Belarus.