The U.S. praised Turkey's efforts to secure a deal for Ukrainian grain exports, the State Department said Thursday.

"We applaud the diligent work of our Turkish allies," State Department spokesperson Ned Price told reporters, also lauding U.N. Secretary-General Antonio Guterres for his "hard work" in securing the deal.

The agreement is expected to be signed Friday in Istanbul, according to the Presidential Communications Directorate. President Recep Tayyip Erdoğan and Guterres will be present for the signing ceremony, with the participation of Russian and Ukrainian delegations at Dolmabahçe Presidential Office in Istanbul.

Last Thursday, Ankara said there is a consensus regarding establishing an operations center in Istanbul that will monitor the implementation of a potential sea corridor in the Black Sea to export grain from Ukraine.

Russia and Ukraine account for nearly a third of global wheat supplies, while Russia also exports fertilizer and Ukraine corn and sunflower oil. But Ukrainian grain shipments from its Black Sea ports have stalled since Russia invaded, with some 20 million tons of grain stuck.

The U.N. has appealed to both countries, as well as maritime neighbor Turkey, to create a sea corridor for Ukrainian grains to be exported from the Black Sea. Turkey has been coordinating with Russia and Ukraine to agree to a plan that would restart grain exports from Ukrainian ports.

Ankara has held talks with Moscow and the U.N., but says all sides need to meet for a final agreement.

Ankara has offered to host an "observation mechanism" to be formed to monitor the implementation of the sea corridor plan in Istanbul.

While Moscow wants certain Western sanctions lifted to help facilitate grain and fertilizer exports, Kyiv seeks security guarantees for its ports to agree to the U.N.-led plan.