Gunfire rang out in Kyiv. Not Russian. Two Ukrainian secret services shot at each other, three people were wounded, two of them seriously - one has a severed artery in his leg and is in critical condition. This is not news from the front. This is an internal reckoning, in the capital, in the middle of a war.

President Volodymyr Zelensky called the situation "absolutely shameful". The sentence he said next lands harder: "In Ukraine, weapons are fired only at the Russian occupiers. Our state will never look at any other kind of shooting as something somebody was permitted to do."

What happened, depending on who you ask

The Security Service of Ukraine (SBU) said it had been investigating a Russian terrorist plot against members of the Russian opposition. According to sources in the Ukrainian defence forces speaking to the Kyiv Independent, the target of the alleged plot was Stepan Kaplunov, deputy commander of the Russian Volunteer Corps - a paramilitary unit fighting on Kyiv's side.

The corps reports to the military intelligence agency HUR. Kaplunov attended the Independence Day celebration on 24 August. Yesterday the corps posted on Telegram that "unknown persons snatched him from the yard of his home".

The prosecutor's office then said SBU officers had been attacked by "one of the units of the Ukrainian armed forces" while carrying out investigative actions. Presidential adviser Dmytro Lytvyn said both the SBU and HUR took part in the incident, and that Zelensky had summoned the heads of both services to account.

The other version

The commander of HUR's Tymur special unit tells a completely different story. In a video for Radio Free Europe he said Kaplunov had been "snatched in broad daylight" by SBU officers and held without charge. According to him, after a legal agreement was reached, the SBU began arresting HUR personnel and opened fire on unarmed people.

Lawyer Taras Borovsky claims three HUR members were wounded. He rejects the SBU's claim that it prevented an assassination and says it is an attempt to justify unlawful detention. Kaplunov, he says, has been released, but nobody knows where he is.

What this means

Zelensky signed a decree dismissing Oleh Khramov, head of the SBU's department for the protection of state secrets. The prosecutor's office and the State Bureau of Investigation are to establish what happened. Kyrylo Budanov, head of the president's office, called for a "thorough and impartial investigation".

Clashes between HUR and the SBU are not common. In March 2022 the body of banker Denys Kireyev was found in central Kyiv with a gunshot wound. Kireyev worked for HUR and had allegedly obtained intelligence on Russian invasion plans. He took part in the 2022 peace talks and was later suspected of treason. In 2023 the president's office explained his death as "poor coordination of the Ukrainian services at the start of the war".

Three and a half years on, coordination is evidently still a problem. A state defending itself against invasion cannot afford to have its own services treating each other as the enemy - and yet it happened, and it happened in public.

The question Western partners now have to ask themselves is not whether Ukraine can hold the front. It is who actually commands whom in Kyiv.