ST. PETERSBURG, Feb. 26 (Xinhua) -- Russia's Federal Security Service (FSB) has thwarted a planned terrorist attack targeting a senior military officer in St. Petersburg.

People walk on the frozen Fontanka River in Saint Petersburg on January 29, 2026. (File photo: AFP)

Two Russian citizens were detained on suspicion of preparing the attack, which was coordinated by Ukrainian special services, the FSB said Thursday.

The detainees confessed to the crime. A decision is being made on whether to open a criminal case.

The suspects had communicated via the messaging platform Telegram with representatives of Ukrainian intelligence. Acting on instructions from their handler, they retrieved an improvised explosive device from a hiding place, conducted surveillance at the residence of the intended target, and planted a bomb under the officer's vehicle, the FSB said.

FSB officers discovered and defused the device before it could be detonated.