Russia said on Thursday it would not extend the UN-brokered Black Sea grain deal beyond May 18 unless the West removed a number of obstacles to Russian grain and fertilizer exports, AFP reported.

The United Nations and Turkey agreed on a deal to export grain from Ukraine to the Black Sea last July to help ease a global food crisis exacerbated by a conflict that has disrupted exports from the world’s two leading grain suppliers.

“Without progress in solving five systemic issues … there is no need to talk about the further expansion of the Black Sea Initiative after May 18,” the Russian Foreign Ministry said in a statement.

“We note that despite all the loud statements about global food security and assistance to countries that need it, the Black Sea Initiative served and continues to serve exclusively Kyiv’s commercial exports in the interests of Western countries,” the ministry added.

To persuade Russia to allow Ukraine to resume grain exports from the Black Sea last year, a separate three-year deal was also struck in July, under which the UN agreed to help Russia with food and fertilizer exports.

Russia said the two agreements were “interrelated parts of a single package” and reprimanded the UN Secretariat for what it called a distortion of the facts.

U.N. spokesman Stephane Dujarric said “discussions and communication with the parties are ongoing” and that U.N. officials are determined to enforce both agreements.

He said that with regard to Russian exports, “there are still many critical issues that need to be resolved in terms of payments and other technical issues” that UN officials are trying to resolve.

But he noted that “there were certain concrete results that contributed to an increase in the volume of grain trade, a decrease in freight rates and an increase in the number of ships calling at Russian ports for fertilizers and a decrease in insurance.”

“So we’ve made some progress, but we’re still looking to do more,” Dujarric said.