"I'm sure Greta is a kind girl and very sincere," Vladimir Putin had said.

Swedish climate campaigner Greta Thunberg has responded with wry humour on Twitter to patronising comments made about her by Russian President Vladimir Putin.

The 16-year-old changed her Twitter biography to say "A kind but poorly informed teenager" after Putin described her in these terms at a Moscow forum this week.

On Wednesday, Putin said: "I don't share the general enthusiasm" for Greta Thunberg's impassioned speech at the United Nations climate summit in September, which went viral with her repeated question: "How dare you?"

"I'm sure Greta is a kind girl and very sincere," Putin said of the campaigner who sailed across the Atlantic instead of flying to speak at the UN.

However, "no one explained" to Thunberg, who has 2.7 million followers on Twitter, that "the modern world is developing quickly," he lamented.

Putin said it was praiseworthy for young people to raise environmental issues, but raised the possibility that someone was manipulating Thunberg "in their own interests".

He warned "adults must do all they can not to lead teenagers and children into any extreme situations."

US President Donald Trump also attempted to crush Thunberg, only for her to use his own words against him.

After her speech at the UN, Trump mocked her tone on Twitter, saying she "seems like a very happy young girl looking forward to a bright and wonderful future."

Thunberg later changed her Twitter biography to read: "A very happy young girl looking forward to a bright and wonderful future."

Thunberg has been tipped as a possible winner of this year Nobel Peace Prize.