02:28
The summit between Putin and Trump could mark a warming of relations between the two global powers. But deep disagreements remain.
November 2016. Vladimir Putin lost no time in congratulating Donald Trump on winning the presidential election. Their friendly interaction surprised the world, coming not long after a mass expulsion of Russian diplomats over allegations of Russian interference in the election. Now there were expectations of brighter relations.
But after Trump ordered a missile strike on a Syrian airbase in April 2017, the mood in Moscow changed.
VLADIMIR PUTIN RUSSIAN PRESIDENT "It is possible to say that the level of trust on a working level, especially on the military level, it has not improved, but rather has deteriorated."
Trump also fired his National Security Advisor Michael Flynn and his Chief Strategist Steve Bannon, both of whom were seen to be pro-Russia.
In December last year, Trump unveiled his first National Security Strategy, saying Russia "challenges" American power, influence, and interests. Russia was mentioned more than 20 times, and its nuclear weapons were said to be the biggest security threat.
In March 2018, after the poisoning of an ex-Russian spy in the UK, Washington joined a collective action by western countries to expel Russian diplomats. This second expulsion for the US was a record 60.
In other areas, The US and EU have imposed economic sanctions against Russia over the conflict in Eastern Ukraine. And Russia's role in the Middle East and other regional issues has been highlighted, raising serious concerns in the US.
Then came the turnabout at this year's G7 Summit.
DONALD TRUMP US PRESIDENT "I think it would be an asset to have Russia back in. I think the G8 would be better. I think having Russia back in would be a positive thing."
Trump seemed to be courting Russia again. And Vladimir Putin has been positive during John Bolton's visit to Moscow.
VLADIMIR PUTIN RUSSIAN PRESIDENT "The visit of Mr. Bolton is a hope for our two governments to take the first step towards a comprehensive restoration of relations."
Almost two years on, so far the two leaders have only met at a few international events. Amid many contradictions, the summit between Trump and Putin will be a big step for the relations between the two world powers.