A train derailment that ignited tankers loaded with yellow phosphorous has prompted health authorities in Ukraine to check 16,000 people for symptoms of chemical poisoning.

The number of people treated for exposure to toxic smoke from a phosphorus fire in Ukraine more than tripled today, from 20 to 69, a day after a train loaded with the chemical derailed and caught fire.

Investigators today combed through the wreckage of a Russian passenger jet that crashed into a Ukrainian field during a severe thunderstorm, killing all 170 people aboard.