Ukraine says it thinks Vladimir Putin is planning a new invasion, and it's not hard to see why: the Russian leader has built up troops on its border and resumed the hostile rhetoric that preceded his annexation of Crimea two years ago.

But despite appearances, some experts say Putin is more likely seeking advantage through diplomacy than on the battlefield, at least this time around.

"It's about sanctions," said Andrey Kortunov, director-general of the Russian International Affairs Council, a Moscow-based foreign policy think tank close to the Russian Foreign Ministry.