The Ukrainian Foreign Minister Dmytro Kuleba said on Friday peace negotiations with Russia were difficult and vowed not to back down on its demands.

"The negotiation process is very difficult," Kuleba said in a post on Facebook.

"The Ukrainian delegation has taken a strong position and does not relinquish its demands. We insist, first of all, on a cease-fire, security guarantees and territorial integrity of Ukraine," he added.

He also said there had been "no consensus" on key points with Russia.

"In particular, the Ukrainian language is and will be the only one state language in Ukraine," he said.

He was speaking after President Recep Tayyip Erdoğan said Friday that Kyiv and Moscow appeared to have reached agreement on four key negotiating points, including the language issue.

While Kuleba said this was not true, he said Ukraine "is sincerely grateful" to Turkey "for their political and humanitarian assistance, as well as diplomatic efforts aimed at ending Russia's war against Ukraine."

Moscow has for years alleged that Russian speakers in Ukraine are discriminated against, and has stated this as a key reason for sending troops to the country.