File Photo: Ukrainian soldiers keep position on the front line in the Kharkiv region on July 23, 2022, amid the Russian invasion of Ukraine. AFP
The announcement came a day after Kyiv's artillery struck a key bridge in Moscow-controlled territory in southern Ukraine, damaging an important supply route as Ukrainian forces look to wrest back control of the region of Kherson.
Members of the Russian guard detained 21 "accomplices" of the Ukrainian armed forces and the SBU security service in the Moscow-occupied region of Kherson and the partially controlled region of Zaporizhzhia, the pro-Kremlin regional administration in Kherson said.
Various weapons and ammunition including 53 hand grenades and more than 24 kilogrammes (53 pounds) of explosives have been seized.
State news agency RIA Novosti, citing a member of Russian law enforcement, described the detained agents as a group of gun layers -- who help adjust the aim of fire against targets -- headed by a female coordinator.
They helped aim rocket and artillery fire at the Russian army in the region of Kherson, RIA Novosti said.
Ukraine's bid to oust the Kremlin's forces has been bolstered by longer-range Western weapons that have allowed Kyiv to target Russian supply lines deeper in occupied areas.