Experts say a mystery mass illness in Russia's conflict-torn republic of Chechnya was caused by ethyl glycol - a toxic chemical found in anti-freeze.
Nearly all of those who have fallen ill are girls and women
Blood samples from five affected girls showed traces of ethyl glycol, medical experts in neighbouring Dagestan said.
But their findings were rejected by a separate team of doctors from Moscow and army medics working in Chechnya.
Eighty-five people are suffering from the mystery illness - most of them girls, Russian media report.
In the past week the victims have suffered breathing problems, headaches, irrational fear and panic attacks.
The symptoms prompted speculation that they might have been targeted by chemical weapons.
Muminat Khadzhayeva, a doctor in Dagestan, dismissed such speculation, saying traces of ethyl glycol had been found in blood samples.
Another doctor in Dagestan, quoted by Reuters, said the victims had probably ingested the chemical through a contaminated water supply.
Separatist fighters have waged a bitter war against Russian federal forces for a decade, with attacks taking place both inside the republic and elsewhere in Russia.
Earlier, some Chechen officials said they believed the illness to be psychological "trauma".
Chechnya's infrastructure was left devastated by the war and the healthcare system is short of funds and equipment.