RADIOACTIVITY levels at least doubled during fires that swept through several ghost towns around the stricken Chernobyl reactor this week, engineers said yesterday.
But others claimed that the fires which struck five abandoned, villages and at least 250 around the Chernobyl plant site of the world's worst civilian nuclear disaster 10 years ago did not increase long term radioactivity levels.
The engineers said that the rates went up two or three times, but would return to normal in a few days once the fires - which draw radioactivity from the soil and throw it into the atmosphere to be picked up by the wind - are brought under control.
The fires came shortly before the 10th anniversary of the meltdown in Chernobyl's No 4 reactor on April 26th, 1986.
One official acknowledged that some of this week's fires may have been caused by a clean up operation aimed at brightening up the forsaken area for the anniversary.
"There are brush fires everywhere. You clear an area, and it suddenly catches fire," he said.
But officials from Ukraine's ministry for the aftermath of the Chernobyl disaster blamed some of the fires on former villagers who came to mourn relatives who died in the disaster. Some 150 of them were evacuated because of the fires.
Officials say the region is already so contaminated that small fires make little difference.
Western experts who went to the power plant on Tuesday said there was excess contamination that could last some time, even though a lack of wind helped limit the spread of radioactive particles.
In Geneva, the UN Economic Commission for Europe warned: "Without immediate action, the problem of the contaminated forests around Chernobyl will constitute a major radiological and ecological risk."
After the 1986 disaster nearly five million hectares (12.3 million acres) of forest in Russia, Belarus and Ukraine "were transformed into a radioactive powder keg," the committee said.
It warned that a major fire in the area would be a "time bomb".
A few hundred people - mostly elderly - have returned to live within the exclusion zone, but none in the no go area, authorities said.
Thousands of people died in the aftermath of the 1986 accident, and nearly 135,000 people in Ukraine were evacuated from contaminated areas.
Each year 5,000 to 10,000 people are allowed to enter the restricted zone at this time, to clean headstones in cemeteries. This year at least three times as many are expected.
. At a press conference in Dublin yesterday the Fianna Fail MEP, Mr Jim Fitzsimons, appealed to the international community to provide protective clothing, vehicles, tools, instruments to measure radioactivity, and robots.