Ukraine on Wednesday invited the worried mothers of Russian troops captured on the battlefield to come and collect their sons, in an apparent attempt to embarrass Moscow.

"A decision has been taken to hand over captured Russian troops to their mothers if they come to collect them in Ukraine, in Kyiv," the Defense Ministry said in a statement.

A week into Russia's invasion of Ukraine, Kyiv claims to have captured dozens of Russian servicemen, and cellphone videos are circling online of bewildered and disarmed young men in uniform.

Kyiv has sought to undermine Russian public support for the invasion by opening a telephone hotline for Russian parents to find out if their sons are among the dead or captured.

The Defense Ministry has published telephone numbers and an email address to provide information about captured Russians, and mothers will be invited to Kyiv to collect their missing sons.

"You will be received and taken to Kyiv where your son will be returned to you," the ministry statement said.

"Unlike (Russian President Vladimir) Putin's fascists, we Ukrainians are not waging war against mothers and their captured children."