Barack Obama visits Russia

Barack Obama, his wife, Michelle, and their daughters, Sasha and Malia, step off Air Force One in Moscow Photograph: Dmitry Kostyukov/AFP/Getty Images

The motorcade arrives at the Tomb of the Unknown Soldier in Moscow Photograph: Natalia Kolesnikova/AFP/Getty Images

Barack and Michelle Obama participate in a wreath-laying ceremony at the Tomb of the Unknown Soldier Photograph: Natalia Kolesnikova/AFP/Getty Images

Obama lays a wreath Photograph: Charles Dharapak/AP

Obama during the wreath-laying ceremony Photograph: Natalia Kolesnikova/AFP/Getty Images

Obama during the wreath-laying ceremony Photograph: Sergei Ilnitsky/EPA

Russian honour guards lay a wreath as Obama watches Photograph: Jim Watson/AFP/Getty Images

Obama during the wreath-laying ceremony Photograph: Natalia Kolesnikova/AFP/Getty Images

Michelle Obama with the Russian first lady, Svetlana Medvedeva, at the Kremlin Photograph: Vladimir Rodionov/AFP/Getty Images

Obama sits alongside the Russian president, Dmitry Medvedev, during their Kremlin meeting Photograph: Saul Loeb/AFP/Getty Images

Obama and Medvedev shake hands Photograph: Haraz N Ghanbari/AP

Obama and his family walk through the Kremlin in Moscow Photograph: Sergei Guneev/AFP/Getty Images

Obama walks with Medvedev to a meeting at the Kremlin Photograph: Shawn Thew/EPA

Obama makes his opening remarks at a meeting with Medvedev at the Kremlin Photograph: Shawn Thew/EPA

Obama, sitting alongside the US commerce secretary, Gary Locke, listens to a translator Photograph: Saul Loeb/AFP/Getty Images

Kremlin doors are opened by honour guards as Medvedev prepares to enter with Obama for the signing of the joint understanding on strategic arms eeduction and joint press conference Photograph: Anatoly Maltsev/EPA

Medvedev and Obama arrive to sign the joint understanding on strategic arms reduction Photograph: Anatoly Maltsev/EPA

Obama and Medvedev sign documents on nuclear arms reduction before their joint news conference at the Kremlin Photograph: Jim Young/Reuters

Obama gestures next to Medvedev during their joint news conference at the Kremlin. The pair agreed a target for cuts in nuclear arms and a deal to let US troops fly across Russia Photograph: Jason Reed/Reuters

The two presidents and their wives walk at the Gorki residence outside Moscow Photograph: Vladimir Rodionov/EPA

Obama meets the Russian prime minister, Vladimir Putin, for the first time. The US president described their talks at Novo Ogaryovo as 'an excellent opportunity to put US-Russian relations on a strong footing'. Photograph: Haraz N. Ghanbari/AP

7 July 2009: President Barack Obama and Russian Prime Minister Vladimir Putin converse while having traditional Russian tea and snacks on a terrace at Putin's residence in Novo-Ogarevo on July 7, 2009. Obama praised Vladimir Putin's 'extraordinary work' as Russia's president and now prime minister, but admitted their two nations still do not agree on everything Photograph: Alexey Druzhinin/AFP/Getty Images

President Barack Obama delivers a speech at the graduation ceremony of the New Economic School in Moscow Photograph: Saul Loeb/AFP/Getty Images

President Barack Obama and US first lady Michelle Obama greet graduates and audience members after speaking at the National Economic School graduation in Moscow Photograph: Charles Dharapak/AP