VIENNA - (AP) - The Japanese nuclear accident that has sparkedworldwide radiation fears ranks "in between" those that occurredat Chernobyl and Three Mile Island, a U.N. expert said Wednesday.

Wolfgang Weiss, chairman of the U.N. Scientific Committee on theEffects of Atomic Radiation, said it's far too early to even beginan assessment of the situation at the Fukushima Dai-ichi plantbecause the crisis there is ongoing.

But, he noted, while radioactivity from the 1979 Three MileIsland incident in the United States was largely contained, tracesof fallout from Fukushima detected around the world are "much,much, much lower" than traces seen at similar distances after the1986 Chernobyl disaster in Ukraine.

The six-reactor Japanese complex was crippled by anearthquake-triggered tsunami on March 11 and has been seepingradiation into the environment. Authorities are struggling to getthe situation under control and have indicated that could takemonths.

When reporters asked Weiss how he compares the Japanese crisisto its two predecessors, he said: "It's in between. It's not asdramatic as Chernobyl, but it's certainly much more serious than"Three Mile Island.

Weiss, who also heads the radiation protection and healthdepartment at Germany's Federal Office for Radiation Protection,noted that Fukushima's proximity to the Pacific Ocean wasbeneficial in containing the contamination and exposure to people.

"The Pacific takes it all and there we have huge dilution,"Weiss said.

Fred Mettler, a member of the U.N. committee, agreed, notingthat in contrast to Fukushima Chernobyl was surrounded by land.During that disaster, hundreds of people were exposed to very highdoses of radiation and 135 got acute radiation sickness, he added.

"We haven't seen any of that at Fukushima, so the earlymanagement by the Japanese here is very different from whathappened at Chernobyl," Mettler said.