Experts convened by the World Health Organization has decided that cellphones might pose a risk of brain cancer in humans.

The finding that cellphones are a possible carcinogen is a bit of surprise. Only last year, a WHO-organized study of cellphone risks that was the largest conducted to date found scant evidence to support a link between cellphones and brain cancers.

But a group of 31 experts from 14 countries conducted a review of the scientific literature and determined that the evidence, though limited, could support a connection between cellphone use and two types of brain cancer — gliomas and acoustic neuromas. (A summary of the findings is described in this press release.)

The evidence didn’t support a link between the electromagnetic radiation emitted by cellphones with other cancers.

And, it should be pointed out that the group, working under the auspices of the International Agency for Research on Cancer, didn’t put a number on the increased risk. “The evidence, while still accumulating, is strong enough to support a conclusion,” said a statement by Dr. Jonathan Samet, a University of Southern California epidemiologist who chaired the panel of experts. “There could be some risk, and therefore we need to keep a close watch for a link between cell phones and cancer risk.”

Cellphones got labeled as risk level “2B” in the IARC system, a designation that covers a long list of chemicals, including gasoline and lead, as well as the occupational hazard that comes with being a firefighter.

The findings by the cancer experts will be evaluated by WHO and health agencies in individual countries.

The full review will be published in the July 1 issue of the medical journal The Lancet Oncology and will be available online in a few days, the WHO’s IARC said.