(CNN) Hillary Clinton took aim at President Donald Trump's much-anticipated meeting with Russian President Vladimir Putin, calling into question her former presidential campaign rival's loyalties just hours after he tweeted a congratulations to the hosts of the World Cup.

"Great World Cup. Question for President Trump as he meets Putin: Do you know which team you play for?" Clinton tweeted Sunday night, ahead of the President's first official summit with Putin, taking place in Helsinki, Finland.

Great World Cup. Question for President Trump as he meets Putin: Do you know which team you play for? — Hillary Clinton (@HillaryClinton) July 16, 2018

Earlier Sunday, Trump tweeted out congratulations to the tournament's victors, France, as well as Putin and his countrymen for "putting on a truly great World Cup Tournament -- one of the best ever!"

Congratulations to France, who played extraordinary soccer, on winning the 2018 World Cup. Additionally, congratulations to President Putin and Russia for putting on a truly great World Cup Tournament -- one of the best ever! — Donald J. Trump (@realDonaldTrump) July 15, 2018

Clinton followed up on her jab at the President on Monday evening following the summit, when she wrote: "Well, now we know."

Clinton's remark comes after Trump received sweeping criticism for his comments about Putin and the US intelligence assessment of Russian interference in the 2016 election.

Read More