Mobile phone radiation may damage cells by increasing the forces they exert on each other, scientists have said.
Evidence on mobile phone health risks is inconclusive
The finding could be the key to claims that mobile phones cause cancer and other health problems.
Swedish physicists looked at the effect of electromagnetic radiation on red blood cells using a mathematical theory, New Scientist reported.
Experts cautioned that the finding was theoretical and said there was no evidence of a danger to health.
There have been suggestions that mobile phones can cause brain tumours and Alzheimer's disease, but research has been inconclusive.
The conventional view has been that radio waves could only damage a cell if they were energetic enough to break chemical bonds or "cook" tissue.
But radiation given off by mobile phone handsets is too weak to do this.
Bo Sernelius at Linkoping University, Sweden, looked at another possibility by modelling the properties of red blood cells.
Water molecules have poles of positive and negative charge which create forces between cells. These forces are normally extremely weak - about a billion-billionth of a newton.
The simplified mathematical model investigated the effect of electromagnetic radiation in the field of 850 megahertz on the blood cells.
850 megahertz is around the range used by some mobile phones, though different networks vary and some phones use around 1800 megahertz.
The molecules all ended up with their poles aligned in the same direction. The forces between the cells unexpectedly jumped by about 11 orders of magnitude.
If confirmed by experiments, the results could give an explanation for tissue damage. Stronger attractive forces between cells might make them clump together or cause blood cells to contract, New Scientist said.
Katie Daniel, deputy editor of the journal Physical Chemistry Chemical Physics, said the finding was important.
"It highlights the idea that electromagnetic radiation might act on cells by affecting the attractive forces between them rather than simply causing heat
damage to tissue," she said.
Camelia Gabriel, from King's College London, who is taking part in the Mobile Telecommunications and Health Research Programme funded by the Government, said the theory was feasible.
But she said the model was extremely simple and may not apply to larger numbers of cells.
"It needs to be tested experimentally," she said.
Dr Michael Clark at the National Radiological Protection Board said: "It is an interesting theory but it is not evidence of an effect on cells or a real health effect. I don't think the author would claim it was."
Recent reviews of the science had not shown there was a danger to health from using mobile phones, he said.
"There is presently no evidence of cancer or any other serious health effect. It is so far so good, but it is early days of course," said Dr Clark.
"The widespread use of mobile phones is a relatively recent phenomenon, particularly by children."