Turkey has halted a Russian-flagged cargo ship off its Black Sea coast and is investigating a Ukrainian claim that it was carrying stolen grain, a senior Turkish official said on Monday.

Ukraine‘s ambassador to Turkey said on Sunday the Zhibek Zholy was detained by Turkish customs authorities. Ukraine had previously asked Ankara to detain it, according to an official and documents viewed by Reuters.

Kyiv has accused Moscow of stealing grain from the territories that Russian forces have seized since their invasion began in late February. The Kremlin has previously denied that Russia has stolen any Ukrainian grain.

“Upon request, the ship named Zhibek Zholy was halted off Karasu (port),” a senior official said. “The allegations are being investigated thoroughly. It is not written on the grain who it belongs to.”

He said Turkey was in contact with Russia, the United Nations and third parties regarding the issue.

On Sunday, Reuters reporters saw the ship anchored about 1 km from the shore and outside of the Karasu port in northwest Turkey’s Sakarya province. At the time there were no obvious signs of movement aboard or by other vessels nearby.

Ukrainian Ambassador Vasyl Bodnar had said on Ukrainian national television that the ship’s fate would be decided by a meeting of investigators on Monday and that Ukraine was hoping for the confiscation of the grain.

A Ukrainian foreign ministry official, citing information from Ukraine‘s maritime administration, told Reuters on Friday the 7,146 dwt Zhibek Zholy had loaded the first cargo of some 4,500 tonnes of Ukrainian grain from Berdyansk, a Russian-occupied port in south Ukraine.