US President Donald Trump held a second - previously undisclosed - conversation with Vladimir Putin at the G20 summit earlier this month.

The White House has confirmed that President Trump and Mr Putin attended a dinner with G20 leaders at the recent Hamburg summit.

However, after the meal, The US President joined the Russian leader for a second – private - conversation.

Ian Bremmer, president of political risk consultancy Eurasia Group, said he spent about an hour talking "privately and animatedly" with Mr Putin.

The White House has disputed Mr Bremmer’s account, saying: "There was no 'second meeting' between President Trump and President Putin, just a brief conversation at the end of a dinner."

Mr Putin's translator was the only other person present during the conversation between the pair but there was no translator for Mr Trump, something Mr Bremmer described as a "breach of national security protocol."

An unnamed White House official said that both men used the Russian translator as Mr Trump's translator did not speak Russian.

The G20 leaders had only been allowed to have one translator attend the dinner with them, the official said, adding that, because Mr Trump had been sitting next to the wife of Japan's Prime Minister Shinzo Abe at dinner, his translator was for Japanese.

The news comes amid a number of investigations into links between the Trump campaign and possible Russian interference in last year’s presidential election.