Russia’s top security agency says it has arrested four Russians accused of making preparations to kill senior Defense Ministry officials on Ukraine's orders.

Russia’s Federal Security Service said on Thursday it had foiled several plots by Ukrainian intelligence services to kill high-ranking Russian officers and their families in Moscow using bombs disguised as power banks or document folders.

According to the Federal Security Service (FSB), four Russians were involved in an alleged Ukrainian plot to assassinate senior military officers.

The bombs were disguised as an electric scooter, a document folder and a magnetized portable charger, Russia's Federal Security Service said.