Ukrainian Security Service officers and National Police have stepped up checks on residents in Kiev-controlled parts of the Zaporozhye and Kherson regions who have relatives living in Russia, representatives of the pro-Russian underground told TASS.

According to the source, people are regularly singled out for searches at checkpoints, with officers examining the contents of their phones. Raids have also become more frequent recently, a development the underground linked to successful Russian strikes.

A Russian phone number, messages exchanged with relatives in Belgorod, Crimea or other Russian regions, or records of money transfers from family members may be used as grounds for detention, the source claimed. Those detained can then be taken for questioning, threatened and accused of high treason.

The underground representative said its own agents had also faced such checks, although Ukrainian security officers had been unable to substantiate their suspicions.

The underground believes the SBU is using these measures not only to identify residents deemed disloyal, but also to pressure and recruit people. According to this account, relatives who remain in Ukraine are used to blackmail family members living in Russia and force them to collect and pass on information.