Gershkovich, 32, became the first US journalist arrested on spying charges in Russia since the Cold War when he was detained by the Federal Security Service (FSB) on March 29 last year.
Russia vetoed the annual renewal of a panel of experts monitoring enforcement of longstanding United Nations sanctions against North Korea over its nuclear weapons and ballistic missile programs.
Four suspected gunmen behind the deadliest attack in Russia in 20 years are Tajik citizens. They have been arrested along with seven other suspects.
"We expect that we will have enough people capable of defending their motherland," Syrskyi said. "I am talking not only about the mobilized but also about volunteer fighters."
Russian investigators claim gunmen behind concert hall attack had ties to Ukrainian nationalists. US dismisses allegations, blaming Islamic State.
Ukrainian officials regularly urge their Western allies to supply more air defense systems and munitions to thwart increasing Russian missile and drone attacks.
The Houthis have vowed to continue their attacks in the Red Sea as long as Israel continues to commit "crimes against Palestinians."