At the gates of the Black Sea, trade is in full swing and passes through Turkey.

Ukraine’s ambassador to Ankara Vasyl Bodnar also accused her on Friday of buying cereals “stolen shamelessly” from her country and exported from the ports of Crimea, annexed by Moscow in 2014.

After the start of the Russian offensive in Ukraine and the first sanctions, the large ships of the international companies gradually withdrew in favor of smaller boats, but more numerous, and their total remains stable (around 40,000 before the war, according to the observers.

From his terrace overlooking the Bosphorus, a unique passageway for traffic between the Black Sea and the Mediterranean, Yörük Isik follows them closely.

“In May alone, we counted at least ten passages including two round trips from three buildings flying the Russian flag … Not to mention those that we would have collectively missed”, assures this “watchman”. “Two again this morning”.

While swiftly condemning the Russian offensive in Ukraine, Turkey opted for neutrality between the two countries and did not join Western sanctions against Moscow.

It banned the passage of military boats from the end of February on the Bosphorus and Dardanelles straits, thus applying the Montreux Convention. But this 1936 Treaty does not authorize it to intercept commercial ships or to search them, argues a diplomatic source in Ankara.

“We only observe their journey over 10 km, before they enter and after they leave” defends this source on condition of anonymity.

A vagueness that suits Ankara well, believes Elizabete Aunina, of the University of Amsterdam: “The vague wording of the Treaty of Montreux opens up many interpretations: it does not consider cargo ships that could be looted. Turkey has therefore interest in sticking to the most basic interpretation,” she said.

On the other hand, the European Union having decreed an embargo on Russian imports, it is more surprising to see tankers under the Greek or Maltese flag going up the Bosphorus, then the Black Sea, to Russian ports.

With a few free-to-use (open source) real-time monitoring applications, a solid network of correspondents – Russian and Ukrainian activists, NGOs) – and satellite images, Yörük Isik “follows the boats from end to end, from loading until the arrival”.

Some freighters load wheat in Ukrainian ports under Russian blockade such as Odessa, Chornomorsk or Mariupol, he says. Borrow the Bosphorus, direction Syria – where Russia retains an operational base – then Lebanon or Egypt.

The “watchman” also identified a flotilla of old Turkish boats, “never seen before in the region”, which suddenly appear under a flag of convenience in the Russian port of Novorossiysk and which he suspects of operating for the benefit of Russian sponsors.

It lists a few very Turkish names: Kocatepe (now Tanzanian), Barbaros (Equatorial Guinea), Hizir (Malta), Sampiyon Trabzonspor (Cameroon)…

Thus, without waiting for the possible establishment of “marine corridors” which Moscow pretends to accept – its Foreign Minister Sergei Lavrov arrives in Turkey on Wednesday to discuss it – Ukrainian wheat is flowing quietly under the authority of Moscow.

– Deprived of insurance –

“We have this information, but not the right to stop or search commercial vessels, unless there is a threat to Turkey”, continues the diplomatic source without denying these accusations.

“If Russia exports Ukrainian products, nothing authorizes Turkey to stop the boats”, confirms Yücel Acer, professor of international law at the University of Ankara. “Unless there is a United Nations resolution”, – a vain assumption as long as Russia sits on the Security Council, he acknowledges.

According to its ambassador, kyiv has “requested Turkey’s help” to stop fraudulent grain exports.

Without openly admitting it, the European Commission has also found holes in the net and is preparing to tighten the screws again, says a source in Brussels: a new set of sanctions against Moscow will deprive European operators of their insurance if their boats are caught red-handed.

“Most of these boats are covered by European and British insurance: with this new package, they will no longer be able to use them”, explains this source on condition of anonymity who announces “a significant impact” of the device.

But Ankara could do more, insists Elizabete Aunina: “after the annexation of Crimea, Turkey banned boats from Crimea in its ports: it could very well do the same today”.

“But she chose a basic interpretation of the Montreux Convention so as not to have to get involved in the conflict,” she says.