A prominent Russian journalist whose TV reports changed between acclaiming President Vladimir Putin to scathing criticism has died. He was 59.

The Govorit Moskva radio station said on Friday that its editor-in-chief, Sergei Dorenko, died of internal bleeding after an aorta rupture. Earlier, media reports said Dorenko lost consciousness while riding his motorbike in Moscow.

Dorenko rose to prominence in the late 1990s with his muck-raking TV reports against the then-Moscow mayor, Yuri Luzhkov, and former prime minister Yevgeny Primakov who were considered to be strong contenders for the Russian presidency and were more popular at the time than Putin.

Dorenko turned against Putin in 2000 when he blamed the newly elected president for a poor handling of a submarine disaster.