US President Donald Trump and his Russian counterpart Vladimir Putin are meeting in Helsinki, Finland, for their first extensive one-one-one meeting.
The leaders, seated together in a room adorned by American and Russian flags at the Finnish Presidential Palace and separated by a small table, shook hands and answered reporters' questions before the summit.
Mr Trump said "the world wants to see us get along".
"We are the two great nuclear powers, we have 90 per cent of the nuclear and that's not a good thing, it's a bad thing," he said.
"And I think we can hopefully can do something about that because it's not a positive force, it's a negative force. So we'll be talking about that among other things."
Mr Trump said the two countries have "great opportunities", and while they had not got along for the past few years, they could have an "extraordinary relationship".
Mr Putin, for his part, said he and Mr Trump have maintained regular contact by phone and meeting at international events but "the time has come to have a thorough discussion on various international problems and sensitive issues".
He added, speaking through a translator: "There are quite a few of them for us to pay attention to."
Mr Trump said the leaders' discussions would involve trade, the military, missiles, nuclear weapons and China, including their "mutual friend", Chinese President Xi Jinping.
He did not mention Russia's alleged meddling in the 2016 US election.
Nor did he mention many of the prominent issues that have lately dogged US-Russian relations: Moscow's annexation of territory from Ukraine, its support for Syria's Bashar al-Assad, as well as Western accusations that it poisoned a spy in England and meddled in elections.
Instead, in the hours before the summit, Mr Trump saved his public criticism for his own country, tweeting: "Our relationship with Russia has NEVER been worse thanks to many years of US foolishness and stupidity and now, the Rigged Witch Hunt!"
The Russian foreign ministry "liked" his tweet.
During the press conference, Mr Trump also praised Mr Putin for Russia's hosting of the World Cup, saying he watched the semi-final and final.
The meeting, in which only the leaders and translators are present, started about 45 minutes late following Mr Putin's delayed arrival to Finland.
It will be followed by a working lunch with aides.
Summit a 'first step': Kremlin
The Kremlin has played down expectations of today's summit.
It said beforehand it did not expect much from the meeting but hoped it would be a "first step" to resolving a crisis in ties.
"Presidents Trump and Putin respect each other and they get along well," Kremlin spokesman Dmitry Peskov said.
"There is no clear agenda. It will be determined by the heads of state themselves as they go along."
While Mr Trump has been abroad since last week, the special prosecutor investigating allegations that Russia interfered to help him win the 2016 presidential election indicted 12 Russians on Friday for stealing Democratic Party documents.
Critics and Mr Trump's own advisers have urged Mr Trump to use the summit to press Putin hard about "malign" activities.
And Mr Trump's foes at home have been scathing about his apparent refusal to criticise Mr Putin.
His 2016 opponent Hillary Clinton tweeted: "Great World Cup. Question for President Trump as he meets Putin: Do you know which team you play for?"
Russia denies interfering in the US presidential election.
The state RIA news agency quoted a Russian source as saying Moscow was "ready to discuss, ready to undertake mutual obligations of non-intervention into internal matters".
Mr Trump has recently said he would raise the alleged election meddling but does not expect to get anywhere.
He has repeatedly noted that Mr Putin denies it, while also saying that it is alleged to have taken place before he became President.
