Since their first meeting in 2009, President Barack Obama and Russian President Vladimir Putin have had a tense relationship. Disagreements over support for Russian-backed Syrian President Bashar al-Assad and Russia's involvement in the Ukrainian conflict have served to highlight the diplomatic differences between the two heads of state.
Monday's U.N. General Assembly meeting in New York is the first time the two leaders have formally met face to face in two years.
Russian President Vladimir Putin and U.S. President Barack Obama at the United Nations in New York City, September 28, 2015. (Chip Somodevilla/Getty Images)
Russian President Vladimir Putin speaks with President Barack Obama during the Asia-Pacific Economic Cooperation Leaders' Meeting in China, November 11, 2014. The two leaders came face to face at the international summit, and although no formal meeting was planned, it was difficult for Obama and Putin not to cross paths. The White House confirmed the president spoke to Putin three times during the summit, and discussed key issues: Iran, Syria, and Ukraine. (Anadolu Agency AFP/Getty)
President Barack Obama talks on the phone in the Oval Office with Russian President Vladimir Putin about the situation in Ukraine, March 1, 2014. The call, made by Putin, came after Russian forces engaged in an escalated confrontation with Ukrainian troops at Ukraine's border. (The White House AFP/Getty)
President Putin welcomes President Obama at the start of the G20 summit in St. Petersburg amid tensions over how to handle conflict in Syria and Russia's harboring of Edward Snowden preceded the G20 summit, September 5, 2013. (ERIC FEFERBERG/AFP/Getty Images)
Britain's Prime Minister David Cameron is flanked by Vladimir Putin and Barack Obama on the second day of the G8 summit in Northern Ireland, June 18, 2013. Tensions between the two presidents reportedly arose from Russian-backed Syrian President Bashar al-Assad. (JEWEL SAMAD/AFP/Getty Images)
President Barack Obama, British Prime Minister David Cameron, Russian President Vladimir Putin, German Chancellor Angela Merkel, along with other G8 leaders take part in the second Plenary Session of the G8 summit at Lough Erne near Northern Ireland, June 18, 2013. To the disappointment of President Obama, President Putin refused to sign a communiqué against Syrian President al-Assad. (WPA Pool AFP/Getty)
Barack Obama holds a bilateral meeting with Vladimir Putin during the G8 summit in Northern Ireland, June 17, 2013. Disagreement over how to handle Syria's civil war spurred much of the tension between the two leaders. Putin did not support arming Syrian rebels, which Obama and several other national leaders saw as justified. (JEWEL SAMAD/AFP/Getty Images)
Obama and Putin converse at Putin's residence outside Moscow in Novo-Ogarevo, July 7, 2009. The two met for the first time after the newly elected President Obama announced a "reset" intended to smooth tense U.S.-Russian relations. Then-Secretary of State Hillary Clinton later symbolically presented Russian foreign services with a red "reset" button that had been incorrectly translated to "overcharge." (ALEXEY DRUZHININ/AFP/Getty Images)
President Obama and President Putin meet at Putin's country residence in Novo Ogaryovo, near Moscow, July 7, 2009. After meeting for the first time, the two were cordial but admitted that their respective nations do not always see eye to eye. (SAUL LOEB/AFP/Getty Images)