In photos: The most difficult handshake of the G20 meeting
A look at Barack Obama and Vladimir Putin at the start of the summit Thursday - and at previous meetings.
Russia's President Vladimir Putin waits for guests before the first working session of the G20 Summit in Constantine Palace in Strelna near St. Petersburg, September 5, 2013.GRIGORY DUKOR/Reuters
Russia’s President Vladimir Putin, left, welcomes U.S. President Barack Obama to the G20 Summit near St. Petersburg, September 5, 2013. Disagreements between Russia and the United States over matters ranging from Syria to Edward Snowden to gay and lesbian rights have overshadowed relations not only between the two governments, but between the two leaders as well.GRIGORY DUKOR/Reuters
Russian President Vladimir Putin and U.S. President Barack Obama reach to shake hands during arrivals for the G-20 summit, Sept. 5, 2013. The Globe's Bill Curry reports that Mr. Putin was on the receiving end of a "stern and somber look" from the U.S. President.Dmitry Lovetsky/The Associated Press
U.S. President Barack Obama, right, shakes hands with Russia's President Vladimir Putin during arrivals for the G-20 summit at the Konstantin Palace in St. Petersburg, Russia on Thursday, Sept. 5, 2013. Mr. Obama cancelled plans for a visit to Moscow for a face-to-face meeting with Mr. Putin after Russian officials snubbed Washington by granting asylum to NSA whistleblower Edward Snowden.Dmitry Lovetsky/The Associated Press
U.S. President Barack Obama, right, speaks with Russia's President Vladimir Putin during arrivals for the G-20 summit in St. Petersburg, Thursday, Sept. 5, 2013. The Globe's Bill Curry reports that while the two leaders smiled for photographers, the personal tension between them was obvious.Alexander Zemlianichenko/The Associated Press
U.S. President Barack Obama, left, walks away after shaking hands with Russia's President Vladimir Putin, right, during arrivals for the G-20 summit Thursday, Sept. 5, 2013. While the two will interact regularly during the proceedings, a spokesman for Mr. Putin said no private meetings are planned.Alexander Zemlianichenko/The Associated Press
U.S. President Barack Obama walks into Konstantin Palace in St. Petersburg, Russia, Thursday, Sept. 5, 2013, after being greeted by Russian President Vladimir Putin, right, at the beginning of the G20 summit. Mr. Putin has been among the most vocal critics of Mr. Obama's plans for military action against Syria.Pablo Martinez Monsivais/The Associated Press
Russian President Vladimir Putin (left) and U.S. President Barack Obama are pictured on a video screen installed in the press centre of the G20 Summit in Strelna near St. Petersburg, September 5, 2013. Echoing statements from Mr. Putin's press secretary, a White House official told reporters that the two leaders will not meet one on one during the summit -- fuelling rumours of a strained interpersonal relationship.GRIGORY DUKOR/Reuters
Earlier meetings between the two have sometimes appeared tense. U.S. President Barack Obama (L) and Russian Prime Minister Vladimir Putin arrive for a meeting in Moscow July 7, 2009.Jim Young/Reuters
U.S. President Barack Obama (L) meets with Russian President Vladimir Putin during the G8 Summit at Lough Erne in Enniskillen, Northern Ireland June 17, 2013.Kevin Lamarque/Reuters
President Barack Obama and Russian President Vladimir Putin reach to shake hands in Enniskillen, Northern Ireland, Monday, June 17, 2013.Evan Vucci/The Associated Press