Two of President Donald Trump's favorite strongmen — Russian President Vladimir Putin and Saudi Crown Prince Mohammed bin Salman — warmly shook hands with one another, smiled broadly and laughed when they were seated together Friday at the G-20 summit in Argentina. Tweet Twitter quickly labeled the Putin-MBS palm slap a "bro-five." Tweet But it wasn't a joking matter for Garry Kasparov, the Russian who is both a former world chess champion and an outspoken critic of Putin, who retweeted the video with the caption: "Murder Incorporated." Their hearty embrace came two days after the Senate overwhelmingly voted to call for an end to U.S. involvement in the Saudi-led war in Yemen, and after weeks of strong suspicion that the Saudi crown prince had ordered the brutal killing of journalist Jamal Khashoggi in the kingdom's consulate in Istanbul last month. WATCH: Who is Mohammed bin Salman?

The bonhomie in Buenos Aires came at the end of a week in which Russia seized several Ukrainian naval ships and their sailors in the Black Sea — and in which Trump's former personal lawyer Michael Cohen pleaded guilty to lying to Congress about the extent of Trump's involvement and knowledge of an aborted plan to build a Trump Tower in Moscow. Special counsel Robert Mueller is continuing to investigate Russian efforts to influence the 2016 president race that ended in Trump's victory, as well as possible collusion by the Trump campaign in that skulduggery. Trump adamantly denies any wrongdoing. Trump, right after Cohen's guilty plea Thursday, told reporters he planned to meet with Putin at the G-20. An hour later, however, the president tweeted that the meeting was canceled in light of Russia's refusal to release the Ukrainian ships and sailors. WATCH: What is the difference between the G-7, G-8 and G-20?