The release of a Russian ship allegedly carrying stolen Ukrainian grain from Turkish waters is "unacceptable," the Ukrainian Foreign Ministry said.
Turkey ignored a request to arrest the vessel and cargo and the ship was released on July 6, according to a ministry statement on Thursday.
It expressed "deep disappointment and appeals to the Turkish side with an urgent request to conduct an investigation ... and provide a full response to the requests of the relevant authorities of Ukraine."
The Russian merchant ship, Zhibek Zholy, had carried the grain from the occupied port of Berdiansk to the Turkish port of Karasu.
"In relation to the unacceptable situation, the ambassador of Turkey in Kyiv was invited to the Ministry of Foreign Affairs," the ministry added.
CNN has reached out to the Turkish government for comment.
The Russian news agency TASS said Thursday that the Zhibek Zholy, "which is anchored in Turkey, plans to leave due to idle time and ship grain to a storage vessel."
"It is planned to go to the accumulative (storage) vessel and trans-ship," TASS said, citing one of the ship's crew members. "Then, when the large vessel is loaded, (it) goes to ports and unloads."
Shipping monitoring data Thursday shows the transponder of the Zhibek Zholy no longer active at its recent anchorage outside Karasu.
Satellite imagery shows that Russian ships frequently offload their cargoes to other vessels in the Black Sea.
Ukraine's Ambassador to Turkey Vasyl Bodnar previously told CNN the Zhibek Zholy was at anchor near Karasu as "it was in fact detained by Turkish customs authorities and it is not allowed to enter the port."
"Now we are waiting for the decision of the relevant authorities of Turkey regarding the actions that the law enforcement agencies of Ukraine insist on," he added.
Some background: For months, Ukraine and allied countries have been trying to mitigate a growing food crisis caused by Russia’s months-long blockade of Ukrainian ports, with Moscow being accused of using food as a weapon of war.
On Monday, Ukrainian President Volodymyr Zelensky said up to 60 million tons of grain could be stuck in the country by the fall if it continues to face blocked exports.
The UN has said Russia's blockade of Ukrainian ports has already raised global food prices and threatens to cause a catastrophic food shortage in some parts of the world.
Russia has repeatedly denied it is blocking the ports or stealing grain.