Vladimir Putin refused to condemn Donald Trump's decision to withdraw the United States from the Paris climate agreement, saying there is still hope of developing a "common approach" to the challenge of climate change.

Speaking at the annual St Petersburg International Economic Forum on Friday, Mr Putin said the world should not "judge" the US president but work out how to strike a new deal.

"Don't worry be happy," Mr Putin said during a panel session at the forum. "You shouldn't make a noise about this, but should create the conditions for joint work."