Pope Francis called for the lifting of the blockade on wheat exports from Ukraine, saying that grain cannot be used as a "weapon of war".

He said this at the end of a general audience on Wednesday, June 1, Vatican News reported.

"The blockade of grain exports from Ukraine, on which the lives of millions of people depend, especially in the poorest countries, is very disturbing," Pope Francis said, without specifying who is blocking the supply of Ukrainian grain.

"I make a fervent appeal to do everything possible to solve this problem and to guarantee the universal right to food. Please do not use grain, a staple food product, as a weapon in war," he urged.

The African Union has already warned that the blockade could cause a food crisis on the continent.

Russian ships are blockading Ukrainian ports, preventing exports through the Black Sea and the Sea of Azov.

Ukraine has also called for the blockade to be lifted, while Russia claims that Ukrainian maritime territory near the ports is mined.