Members of two militias that oppose Vladimir Putin—the Russian Volunteer Corps and the Free Russia Legion—claimed to have “liberated” several border villages. The groups appear to be based in Ukraine, from where they mount their attacks. Russia says that the militias are a front for the Ukrainian army; Ukraine insists that they are composed of Russian dissidents. The reality is somewhere in between. Both militias do indeed recruit disaffected Russian nationals. Both also co-ordinate their activities with hur, Ukraine’s military-intelligence agency. Yet the groups have no formal connection to the Ukrainian government. That allows Ukrainian officials to distance themselves from the militias’ operations, however implausibly.

The Kremlin sought to downplay the embarrassing security breach. Russian officials described it as an attempt by Ukraine to “deflect attention” from what they claimed was their capture of the long-contested town of Bakhmut on May 20th (Ukraine says it still holds buildings and trenches on Bakhmut’s south-western edge). On May 23rd the Russian defence ministry claimed to have killed or expelled all the militia fighters from Belgorod, though it provided no evidence.

A Ukrainian intelligence source offers a more realistic assessment. Two ideas underpinned the operation in Belgorod, he says. The first was to undermine Mr Putin’s domestic authority: if a strongman can’t guarantee security, what is the point of him? The second was to pull Russian military reserves away from critical sections of the front line, in the run-up to a long-planned Ukrainian counter-offensive.

This is not the first foray by Ukraine-backed militias into Russian territory. The Free Russia Legion and Russian Volunteer Corps were formed last year, under opaque circumstances, but came to prominence this March when they spearheaded an incursion from Ukraine into Bryansk, another border region. Russia claimed that two civilians were killed in that attack, but offered no proof.