By Frank Gardner, BBC Security Correspondent
Weapons dealers in Yemen are openly using the social media platform X, formerly known as Twitter, to sell Kalashnikovs, pistols, grenades and grenade-launchers.
The traders operate in the capital Sana’a and other areas under control of the Houthis, a rebel group backed by Iran and proscribed as terrorists by the US and Australian governments.
"It is inconceivable that they [the weapons dealers] are not operating on the Houthis’ behalf," said the former British Ambassador to Yemen, Edmund Fitton-Brown, who now works for the Counter Extremism Project.
"Purely private dealers who tried to profit from supplying, [for example] the government of Yemen, would be quickly shut down."
An investigation by The Times newspaper found that several of the Yemeni accounts bore the blue tick of verification.
Both The Times and the BBC have approached X for comment, but have not so far received any response.
Most of the platform’s content moderators were laid off after the new owner Elon Musk bought the company in 2022.
The advertisements are mostly in Arabic and aimed primarily at Yemeni customers in a country where the number of guns is often said to outnumber the population by three to one.
The BBC has found several examples online, offering weapons at prices in both Yemeni and Saudi riyals.
The words beside the weapons are designed to lure in the buyers.
"Premium craftsmanship and top-notch warranty," says one advertisement. "The Yemeni-modified AK is your best choice."
A demonstration video, filmed at night, shows the seller blasting off a 30-round magazine on full automatic.
Another offers sand-coloured Pakistani-produced Glock pistols for around $900 each.
Yet these advertisements are not hidden in the depths of the Dark Web, where guns and other illegal items are usually traded, they are in plain sight on X, openly accessible to millions of people.
Commenting on this, UK-based NGO Tech Against Terrorism issued what it called an urgent plea to tech platforms to actively remove Houthi-supporting content on the internet and social media platforms.
The Houthis, a mountain-based tribal minority, swept to power in Yemen in 2014, ousting the UN-recognised government.
Since then, a seven-year military campaign led by neighbouring Saudi Arabia failed to remove them, while the country descended into civil war.
In late 2023 the Houthis, who have an extensive arsenal of drones and missiles, many supplied by Iran, have been targeting commercial and naval shipping in the Red Sea.
The Houthis say this is in support of Palestinians in Gaza, but many of the vessels have had no links to Israel.
A US-led maritime force offshore has failed to stop the Houthis’ attacks on shipping, which have had a disastrous effect on trade passing through Egypt’s Suez Canal.
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