Russian state TV claims Ukrainians are selling US-donated weapons on the dark web. The BBC investigated one such marketplace, spoke undercover to those apparently selling weapons, and gathered evidence that suggests the adverts for weapons are fake.

"Ukrops [a derogatory Russian slang term used to refer to Ukrainians] are selling Javelins on the darknet. The command of the Armed Forces of Ukraine resells equipment and weapons supplied by Nato." This message about anti-tank weapons was posted on 2 June by pro-Kremlin English-language account ASB Military News.

The account has been recently suspended by Twitter but still exists on Telegram, where it has more than 100,000 subscribers.

On the same day, another pro-Kremlin Telegram channel, with 700,000 followers, posted in Russian: "Thanks to Biden and European friends of Ukraine, Javelins, machine guns and even tanks will pop up all over the world in the hands of terrorists and criminals."

Pictures attached to the post showed an advert allegedly selling the FGM-148 Javelin, a US-made anti-tank missile system, for $30,000 (£26,000) and promising to deliver the weapons to the Ukraine-Poland border or abroad.

These posts were quickly picked up by mainstream Russian state TV, which routinely runs stories claiming Ukraine is selling weapons supplied by the West.

We decided to investigate these accusations ourselves using laptops that could not be linked back to the BBC. With a specialised web browser, we accessed the dark web where the level of anonymity attracts criminal activity.

• What is the dark web?

We found several sellers on the same marketplace mentioned by Russian state media outlets. They said they were selling Nato weapons, and their geolocation was Kyiv. However, the name of Ukraine's capital was misspelled in Ukrainian.

This was not the only inconsistency.

Passing Syrian weapons off as Ukrainian

One of the main sellers often mentioned in Russian media reports is known as "Weapons Ukraine".