Although the US president had nothing but warm words for his Russian counterpart ahead of their meeting, their posture upon meeting was significantly more awkward. As they met for a brief photo call before closed-door talks, the two men avoided eye contact and seemed unsure of how best to approach one another, with Trump slouching in his seat and Putin remaining enigmatic.

"They said they think it's Russia; I have President Putin, he just said it's not Russia," said Trump, on assurances from US intelligence agenices that the Russian government meddled in the 2016 presidential elections. This came mere seconds after Putin admitted in a press conference that he had be hoping for him to win over rival Hillary Clinton.

A reporter for the progressive US publication "The Nation" was forcibly removed from the presidents' joint press conference, apparently for holding a sign that seemed to read "Nuclear Weapon Ban Treaty."

After giving a series of rambling answers to questions about Syria and Russian hacking, Trump was asked why he would trust President Putin's assurances over his own intelligence services. He abruptly changed the subject to Hillary Clinton. "Where are those servers?" he asked. "Where are Hillary Clinton's emails?"

President Putin reacted aggressively to questions from US reporters from the new agencies Reuters and the Associated Press. "Can you name a single fact?" he asked. He also swerved around a US reporter's question as to whether he directed government agents to interfere in American politics.

"The ball's in your court," said Putin with an air of forced joviality as he presented Trump with a gift to mark their meeting. Trump had already congratulated the Russian president on "one of the best ever" World Cup tournaments. After he was handed the soccer ball, Trump appeared to surprise onlookers by tossing it into the crowd, where it was given to his wife Melania Trump.

The two men again appeared ill at ease with one another at the end of the press conference, a stark contrast to their vows to work towards stronger ties. Both leaders were uncomfortably prompted to deny the existence of a "dossier" of compromising material collected by Russian agents during Trump's visits to the country before he was president.

Even before taking office, US President Donald Trump's relationship with NATO has been a tumultuous one, to say the least. He has disparaged the trans-Atlantic alliance, once describing it as "obsolete" and a relic of the Cold War. Here are Trump's most memorable quotes about the military alliance, even if they are at times false.

While on the campaign trail in 2016, Trump made clear that he saw NATO as a relic of the Cold War. "You know, we're dealing with NATO from the days of the Soviet Union, which no longer exists. We need to either transition into terror or we need something else." But his remarks didn't account for how the alliance backed the US well after the collapse of the Soviet Union, especially in Afghanistan.

Trump has made defense spending his main talking point on NATO. But he has falsely accused member states of owing money to Washington, saying: "Germany owes vast sums of money to NATO, and the United States must be paid more for the powerful, and very expensive, defense it provides to Germany." The problem is NATO doesn't work like that. No money is owed to the alliance for defense or otherwise.

Days before his inauguration, Trump caught NATO members off guard when he claimed the alliance was "obsolete" and threatened to withdraw support. "I said a long time ago that NATO had problems: Number one, it was obsolete, because it was designed many, many years ago." Months later, he retracted his statement, citing changes within the alliance. "Now they fight terrorism," he said.

Trump had tended to lump trade between US allies with how much Washington spends on defense. "We are spending a fortune on military in order to lose $800 billion (in trade losses). That doesn't sound very smart to me," Trump said. The problem is that while NATO members have agreed to spend 2 percent of their GDP on defense, the alliance has nothing to do with international trade.

During a 2018 rally in Montana, Trump hit out at European allies, saying: "They want (us) to protect against Russia, and yet they pay billions of dollars to Russia, and we're the schmucks paying for the whole thing." Trump was referring to Russia as Europe's primary source for oil and natural gas, but he created a false dichotomy between energy reliance and NATO's defense spending goal.

In an interview with Fox News, Trump was asked why the US should jump to the defense of NATO ally Montenegro if it was attacked. The president said he asked himself the same question, a remark that appeared to undermine the alliance's collective defense clause. Trump went on to describe Montenegrins as "very strong" and "very aggressive," and that that aggression risked starting World War III.

Born in St.Petersburg in 1952, Putin signed up with the Soviet intelligence agency the KGB right out of law school in 1975. His first assignment was to monitor foreign nationals and consulate employees in his home city, then called Leningrad. He was then assigned to Dresden, East Germany. He reportedly burned hundreds of KGB files after the fall of the Berlin Wall.

Putin was one of the deputies to St Petersburg Mayor Anatoly Sobchak from 1991 to 1996. Sobchak met Putin at Leningrad State University and the two men were close until Sobchak's death in 2000. Despite accusations of corruption, Sobchak was never charged.

Putin quickly leapt from St.Petersburg to Moscow. In 1997, President Boris Yeltsin gave Putin a mid-level position on his staff — a position Putin would use to cultivate important political friendships that would serve him in the decades to come.

Putin was deeply affected by Anatoly Sobchak's death in 2000. After the apprentice outstripped his teacher politically, Sobchak became a vocal early proponent of Putin's bid for the presidency. A year earlier, Putin used his political connections to have fraud allegations against Sobchak dropped, the beginning of a pattern for friends of the former spy.

In June 2000, Boris Yeltsin stepped down, leaving his prime minister to become interim leader. As he was running for his successful presidential campaign, corruption allegations from his time on the city government in St.Petersburg resurfaced. Marina Salye, the lawmaker who brought up the claims, was silenced and forced to leave the city.

When Putin was constitutionally barred from running for a third consecutive term in 2008, his Prime Minister Dmitry Medvedev ran in his stead. When Medvedev was elected, he appointed Putin as premier. This led to criticism of a "tandemocracy," in Moscow, with many people believing that Medvedev was Putin's puppet.

In March 2018, Vladimir Putin was elected to his fourth term as president. Because the presidential term has been extended, this means Putin will be in power for the next six years. However, the election was marred by a lack of opposition to the incumbent, as well as allegations of vote tampering and ballot-stuffing.

Less than two years after his latest election victory, Putin unexpectedly announced sweeping constitutional changes that prompted his most loyal ally, Dmitry Medvedev, to resign. He was replaced by little-known Mikhail Mishustin (R). Soon after that, Putin hinted he was willing to run again when his current term expires in 2024.