The UN Secretary General Antonio Guterres sent a letter to Russian President Vladimir Putin on Tuesday suggesting a way to further ease the Russian food exports and fertilizers and to ensure the Ukrainian grain exports through the Black Sea.

“The aim is to remove obstacles affecting financial transactions through the Russian Agrarian Bank (RAB), which Russia has expressed concerns about, and at the same time to continue the export of Ukrainian grain through the Black Sea,” the spokesman said. Guterres, Stefan Dujarric.

The agreement allowing grain and fertilizer exports from Ukraine is set to expire on Monday.

Three sources with knowledge of the talks told Reuters that the European Union is considering linking a subsidiary of the Russian Agricultural Bank to the international Swift system to allow trades for food and fertilizer purchases. Two sources said Guterres suggested to Putin that the existing agreement to export grain through the Black Sea be maintained for several months until that subsidiary is linked to Swift.