Drones are “ubiquitous, because they are quite useful, and they're demonstrating that every day in Ukraine,” one analyst told NBC News.

Explosions in the morning and afternoon rocked the symbolic bridge, but after several hours of closure, authorities said the span connecting Crimea to Russia, had reopened.

Representatives from Russia and Ukraine gather for peace talks in Istanbul. The meeting comes after the two countries each launched large-scale drone attacks on one another over the weekend, including an audacious Ukrainian strike on Russia's bomber aircraft fleet.