Russia’s envoy to the United Nations in Geneva says no real progress has been made in resolving issues raised by Moscow over the Black Sea grain deal, which is set to expire next month.

Separately, Ukraine accused Russia of blocking the passage of four grain ships from its Black Sea ports.

The Kremlin has repeatedly said the deal will not be renewed beyond May 18th unless the West removes obstacles to Russian grain and fertilizer exports.

The Black Sea deal, brokered between Russia and Ukraine by the United Nations and Turkey in July, aimed to prevent a global food crisis by allowing Ukrainian grain trapped by Russia’s invasion to be safely exported from three ports.

The Ukrainian navy claims Russia has effectively stalled the deal by refusing to take part in agreeing upon the routes that four grain ships should take, a process that occurs for each export trip.