Mr Krasovsky was responding to science fiction writer Sergei Lukyanenko who claimed that in 1980 he had heard western Ukrainian children saying: “Ukraine is occupied by Muscovites”. In response, Mr Krasovsky said: “Just drown those children, drown them.”
He also proposed that Ukrainian children could be shoved into huts and burned.
The RT presenter also joked about Russian soldiers raping Ukrainian grandmothers.
Mr Krasovsky’s comments caused a storm on social media and he has been forced to apologise.
RT’s editor-in-chief, Margarita Simonyan, blasted Mr Krasovsky’s comments as “wild and disgusting”.
Russia’s Investigative Committee, which handles serious crimes, is now investigating Mr Krasovsky’s remarks, although it is not clear what Russian law he may have broken, if any.
In response to the remarks, Ukraine has accused RT of inciting genocide.
Russian state television has given a considerable amount of time to presenters and pundits who support the war in Ukraine.
Many Russian TV pundits have called for more aggression against Ukraine.
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He said: “Margarita Simonyan doesn’t want to co-operate anymore with Anton Krasovsky, who calls for Ukrainian children to be killed.
“But with Putin, who kills Ukrainian children, Margarita Simonyan does want to co-operate”.
Mr Krasovsky is a graduate of the Maxim Gorky Literature Institute and came to prominence in 2013 when he revealed he was homosexual during a televised debate about a proposed law about “homosexual propaganda”.
He left the channel and later slammed it as “propaganda” and went on to write an article in the Guardian denouncing homophobia in Russia.
However, earlier this year Mr Krasovsky, who is HIV positive, performed a U-turn announcing that he now supported the “homosexual propaganda” law and prior to his latest outburst had denounced Ukrainians as “animals”.