A smirking Mr Trump wagged his finger at the Russian president and said: "Don't meddle in the election, please."

The pair were holding talks on the sidelines of the G20 summit in Japan.

It was their first meeting since Robert Mueller concluded his investigation into alleged Russian interference in the 2016 US presidential election.

US intelligence agencies concluded that Russia was behind an effort to influence the presidential election with a state-authorised campaign of cyber-attacks and fake news stories planted on social media.

But special counsel Mueller's report found no evidence that the Trump campaign criminally conspired with Russia to influence the election.

The G20 is an annual meeting of leaders from the countries with the largest and fastest-growing economies - and this year is likely to see differences of opinion over climate change, Iran, protectionism and global trade, as well as a host of bilateral meetings between leaders.

Putin: Liberalism is 'obsolete'

Mr Putin smiled as the US president delivered his light-hearted reprimand on election interference.

But he was reserved ahead of the G20 talks with his American counterpart, only commenting that the pair had "things to discuss".

However, in a wide-ranging interview with the Financial Times, published on Friday, he offered his thoughts on both global and domestic politics.

He said liberalism was "obsolete", and praised the rise of populism both in Europe and the US. He also described Mr Trump as a "talented person" who knew how to relate to voters.

"It's a great honour to be with President Putin," Mr Trump said at the outset of the talks on Friday. "We have a very, very good relationship."

On Wednesday, in comments made outside the White House, he refused to disclose what he was planning to discuss with the Russian leader. "What I say to him is none of your business," he told reporters, bluntly.

What else is happening at the G20?

The meeting between the two leaders, their first since a summit in Helsinki last July, came at the start of an eagerly awaited G20 summit in Osaka.

Scheduled meetings and set-piece events can often be overshadowed by the many bilateral talks, such as this, that happen on the sidelines.

French President Emmanuel Macron has said he wants strong wording in support of tackling climate change in any final leaders' statement.

The G20 is an annual meeting of leaders from the countries with the largest and fastest-growing economies

But the issue is a contentious one given that the US is committed to pulling out of the landmark Paris climate agreement signed in 2015.

The work to consolidate various opinions is expected to be "difficult", a Japanese official admitted on Thursday.

The most closely watched talks are set to take place between Mr Trump and China's President Xi Jinping on Saturday, as the two countries try to resolve their bitter trade dispute.

Talks ground to a halt last month when Mr Trump accused China of reneging on its promises and raised tariffs on $200bn (£159.2bn) worth of Chinese goods.

The move came as a surprise to many who had thought the US and China were nearing a trade deal. China retaliated with its own tariff hikes.

But there are reports that a trade truce could be struck over the weekend as the two leaders meet in Osaka.

They last met at another G20 summit in Buenos Aires last year and, following a working dinner, agreed on a 90-day truce to their trade war.

Ahead of the meeting, China warned against protectionist trade measures in comments that have been widely interpreted as a criticism of the US.

"Protectionism and bullying practices are on the rise, posing severe threats to economic globalisation and international order," a Chinese foreign ministry official said on Friday.