President Obama urged Russia on Monday to use its influence over Ukrainian separatists to persuade them to allow international investigators unfettered access to the Malaysia Airlines crash site. Obama, speaking on the South Lawn of The White House said, 'the Russian-backed separatists who control the area continue to block the investigation. They have repeatedly prevented international investigators from gaining full access to the wreckage. As investigators approached, they fired their weapons into the air.' Obama said he'd like Russian President Vladimir Putin to intervene. Obama said, 'Russia has extraordinary influence over these separatists. No one denies that. Russia has urged them on. Russia has trained them. We know that Russia has armed them with military equipment and weapons, including anti-aircraft weapons. Key separatist leaders are Russian citizens. So given its direct influence over the separatists, Russia and President Putin, in particular, has direct responsibility to compel them to cooperate with the investigation.' Obama said it is essential for investigators to access the crash site in a timely manner, 'time is of the essence. Our friends and allies need to be able to recover those who were lost. That's the least we can do.' Separately, the president also said Secretary of State John Kerry was en route to the Middle East to try and negotiate a ceasefire in Gaza. TheStreet's Ruben Ramirez reports from New York.