Chernobyl ceremony honours victims 25 years on

Ceremonies have been held to mark the 25th anniversary of the world's worst nuclear accident.

Russian President Dmitry Medvedev and Ukrainian President Viktor Yanukovych attended a commemoration ceremony at the Chernobyl plant, where a reactor exploded in 1986.

The explosion sent a plume of radiation across Ukraine, Belarus, western Russia and other parts of Europe in 1986, harming or killing possibly thousands of people.