Despite confirmation by Ukrainian President Volodymyr Zelensky, who told me that Turkey had agreed to prevent the passage of Russian warships into the Black Sea, through the Straits of Bosphorus and Alderdenil.

According to a Turkish official, Ankara has not taken a decision to prevent the passage of Russian warships into the Black Sea through the Straits of Bosphorus and Alderdenil.

Zielinsky's announcement came in a statement after he made a phone call to his Turkish counterpart, Recep Tayyip Erdogan.

"I thank the Turkish President and the Turkish people for their great support," Zelensky said.

He added: "The prohibition of the passage of warships into the Black Sea and the provision of substantial military and humanitarian support is crucial today."

He continued: "The people of Ukraine will never forget that."

But Turkey's officials are aware that his country has not taken a decision to close the Straits of Aldardenil and Bosphorus to Russian ships.

Interfax also quoted the Russian Embassy in Turkey as saying that Russia had not received any official notification from Turkey regarding the closure of the Straits of Bosphorus and Alderdenil to Russian warships.

Turkey, which controls the two straits linking the Mediterranean to the Black Sea, has not declared any ban on Russian warships using them.

Its Foreign Minister said Friday that Ankara cannot prevent any warship returning to its Black Sea base from passing through either strait.

Turkey's official Anatolian Agency said that Erdogan informed Zelensky that Turkey was making efforts to reach a truce as soon as possible to reduce further losses to Ukraine.

Turkish Foreign Minister Ould Jawesh Oglu said that his country was considering Kiev's application, but added that "Russia has the right, under the 1936 Montreux Convention, to return ships to their original bases, in this case the Black Sea."

"Even if after a legal process Turkey decides to accept Ukraine's request and close the Straits to Russian warships, only travel in the other direction, far from their original Mediterranean bases, will be prohibited."