Eyes on Putin as tension escalates

A man next to the wreckage of the airliner
A man stands next to the wreckage of a Malaysian airliner carrying 295 people from Amsterdam to Kuala Lumpur after it crashed, in rebel-held east Ukraine, on July 17, 2014.
DOMINIQUE FAGET/AFP/Getty Images

We have reached "the moment of truth" for Russian President Vladimir Putin, said Secretary of State John Kerry after a Malaysian airliner was shot down over Ukraine last week.

President Barack Obama on Monday denounced Russia and the separatists it supports for blocking access to the crash site. It "begs the question: what exactly are they trying to hide?" he said.

President Putin has denied Russia's involvement in the incident.

We'll take a deeper look at the conflict as international tension continues to build.