'It’s like the meeting with Putin is the same thing as him waking up at six in the morning and tweeting.'
Donald Trump has arrived in Hamburg, Germany for the G20 meeting, which includes a Russia meeting for which the US President is said to be "remarkably unprepared".
Mara Liasson, NPR's national political reporter has covered the administration extensively, and expressed concerns over Mr Trump's scheduled one-on-one meeting with Russian President Vladimir Putin.
"The President has been described as having no set agenda, that he’s just going to talk about whatever is on his mind at the moment," Ms Liasson said on the Brian Lehrer Show radio programme.
"It’s like the meeting with Putin is the same thing as him waking up at six in the morning and tweeting," she commented, noting Mr Trump's affinity to use Twitter to communicate with the public about everything from his distaste for the "fake media" to foreign policy matters.
Mr Putin, a former KGB spy, will come with his own agenda, said Ms Liasson.
What may end up being just a so-called "elephant in the room" are the ongoing investigations by the FBI, Senate, House, and special prosecutor Robert Mueller into alleged ties between Russia and members of the Trump campaign team.
There is no indication Mr Trump will discuss that or the January 2017 report which intelligence agencies signed saying that Russia tampered with the 2016 US election.
The biggest names involved in the Trump-Russia investigation
Paul Manafort
Mr Manafort is a Republican strategist and former Trump campaign manager. He resigned from that post over questions about his extensive lobbying overseas, including in Ukraine where he represented pro-Russian interests. GettyMike Flynn
Mr Flynn was named as Trump's national security adviser but was forced to resign from his post for inappropriate communication with Russian Ambassador to the US Sergey Kislyak. He had misrepresented a conversation he had with Mr Kislyak to Vice President Mike Pence, telling him wrongly that he had not discussed sanctions with the Russian. Getty ImagesSergey Kislyak
Mr Kislyak, the Russian ambassador to the US, is at the centre of the web said to connect President Donald Trump's campaign with Russia. ReutersRoger Stone
Mr Stone is a former Trump adviser who worked on the political campaigns of Richard Nixon, George HW Bush, and Ronald Reagan. Mr Stone claimed repeatedly in the final months of the campaign that he had backchannel communications with WikiLeaks founder Julian Assange and that he knew the group was going to dump damaging documents to the campaign of Democratic candidate Hillary Clinton - which did happen. Mr Stone also had contacts with the hacker Guccier 2.0 on Twitter, who claimed to have hacked the DNC and is linked to Russian intelligence services. Getty ImagesJeff Sessions
The US attorney general was forced to recuse himself from the Trump-Russia investigation after it was learned that he had lied about meeting with Russian Ambassador to the US Sergey Kislyak. Getty ImagesCarter Page
Mr Page is a former advisor to the Trump campaign and has a background working as an investment banker at Merrill Lynch. Mr Page met with Russian Ambassador to the US Sergey Kislyak during the 2016 Republican National Convention in Cleveland. Mr Page had invested in oil companies connected to Russia and had admitted that US Russia sanctions had hurt his bottom line. ReutersJeffrey "JD" Gorden
Mr Gordon met with Russian Ambassador to the US Sergey Kislyak during the 2016 Republian National Convention to discuss how the US and Russia could work together to combat Islamist extremism should then-Republican presidential candidate Donald Trump win the election. The meeting came days before a massive leak of DNC emails that has been connected to Russia. Creative CommonsJared Kushner
Mr Kushner is President Donald Trump's son-in-law and a key adviser to the White House. He met with a Russian banker appointed by Russian President Vladimir Putin in December. Mr Kushner has said he did so in his role as an adviser to Mr Trump while the bank says he did so as a private developer. Mr Kushner has also volunteered to testify in the Senate about his role helping to arrange meetings between Trump advisers and Russian Ambassador to the US Sergey Kislyak. Getty ImagesJames Comey
Mr Comey was fired from his post as head of the FBI by President Donald Trump. The timing of Mr Comey's firing raised questions around whether or not the FBI's investigation into the Trump campaign may have played a role in the decision. Getty ImagesPreet Bharara
Mr Bahara refused, alongside 46 other US district attorney's across the country, to resign once President Donald Trump took office after previous assurances from Mr Trump that he would keep his job. Mr Bahara had been heading up several investigations including one into one of President Donald Trump's favorite cable television channels Fox News. Several investigations would lead back to that district, too, including those into Mr Trump's campaign ties to Russia, and Mr Trump's assertion that Trump Tower was wiretapped on orders from his predecessor. Getty ImagesSally Yates
Ms Yates, a former Deputy Attorney General, was running the Justice Department while President Donald Trump's pick for attorney general awaited confirmation. Ms Yates was later fired by Mr Trump from her temporary post over her refusal to implement Mr Trump's first travel ban. She had also warned the White House about potential ties former National Security Adviser Michael Flynn to Russia after discovering those ties during the FBI's investigation into the Trump campaign's connections to Russia. Getty ImagesDuring a stop in Poland before heading onward to Germany, Mr Trump said: "I think it was Russia and I think it could have been other people and other countries. It could have been [that] a lot of people interfered."
He did not name any other countries that could have possibly hacked the US election, however.
" Being unpredictable is not necessarily bad, being unprepared is a different matter," said Ms Liasson. She described Mr Putin as "cagey" and someone who would do a "deep dive" into Mr Trump's psyche, which is clearly on display through Twitter.
North Korea is another topic that will be on the larger G20 agenda.
Ms Liasson said: "North Korea sees nuclear weapons as an insurance policy".
With China and Russia both asking the US to not place new sanctions or use military force to stem the threat from Pyongyang. China's concern is also regional and peninsular security.
Mr Trump has expressed some disappointment with Chinese President Xi Jinping regarding the situation.
The mercurial nature of Mr Trump and the strained relationships he already has with German Chancellor Angela Merkel and French President Emmanuel Macron, may be a worry for Korea's President Moon Jae-in.
He recently visited Washington and it was clear Seoul does not want the US to "take any kind of precipitous action" with Kim Jong-un because of its close proximity to the North Korean border and non-nuclear missiles, according to Ms Liasson.
Climate change, trade, and freedom of the press are all issues Ms Merkel has flagged for the meeting - just a portion of the issues on which Mr Trump has clashed with G20 countries, according to CNN.
The US President has reportedly already met with Ms Merkel privately and the summit officially begins 7 July.