May 26: NATO member Turkey is in negotiations with Russia and Ukraine to open a corridor via the Bosphorus for grain exports from Ukraine, a senior Turkish official told Reuters on Thursday.

According to the news agency, Ukraine's Black Sea ports have been blocked since Russia invaded the former Soviet Union nation on February 24 and more than 20 million tonnes of grain are stuck in silos there.

Russia and Ukraine account for nearly a third of global wheat supplies and the lack of exports from Ukraine is contributing to a growing global food crisis.

"Turkey is negotiating with both Russia and Ukraine for the export of grains from Ukraine," Reuters quoted the official as saying in condition of anonymity because the talks were confidential.

"With a corridor to be opened from Turkey, there was a demand for this grain to reach their targeted markets. Negotiations are still ongoing," the person added.

Russian Deputy Foreign Minister Andrei Rudenko reportedly said on Wednesday that Moscow was ready to provide a corridor for vessels carrying food in return for lifting of some Western sanctions.

According to Reuters, Turkey neighbours Ukraine and Russia on the Black Sea and has good relations with both, even as it has condemned the invasion.

Meanwhile, UN Secretary-General Antonio Guterres has been in touch with Russia, Ukraine, Turkey, the United States and the European Union trying to broker what he calls a "package deal" to resume both Ukrainian food exports and Russian food and fertilizer exports, the news agency further reported.

However, there are many hurdles to any deal, including Russian demands for some sanctions to be lifted in return, the drifting mines, and the prohibitive costs of insuring the maritime route, Reuters reported citing officials and analysts.