Google's chief executive Sundar Pichai, says it is important it and other social media businesses promote "accurate" stories to their billions of users.

Talking to the BBC's Economics editor Kamal Ahmed in the wake of fake news controversies during the US election campaign, Mr Pichai said the firm had made some mistakes.

"There have been a couple of incidences where... we didn't get it right," he said. "It is a learning moment for us and we will definitely work to fix it."