Moscow, 11 July 2022 (dpa/MIA) - Russian President Vladimir Putin and Turkish leader Recep Tayyip Erdogan discussed possible ways to release the grain stuck in Ukrainian ports in a phone call on Monday. It is time for the United Nations to implement the plan for a grain corridor through the Black Sea, according to a statement issued by the Turkish presidential office. Ukraine is a key wheat supplier for many parts of the world but the war and blockades of its ports mean most of the grain is not getting out, causing worldwide food shortages. Many Western countries blame Moscow for the grain crisis and knock-on effects on food security around the world, but Russia has repeatedly denied it is responsible for the problem. The Kremlin said that the two countries also discussed economic cooperation, as well as a planned "Russian-Turkish meeting at the highest level" in the near future. No further details were given. Putin and Erdogan also discussed the situation in Syria during their phone call, both sides said. Erdogan spoke out in favour of extending the cross-border aid mechanism in Syria, according to Ankara, following the expiry of an international agreement on humanitarian aid for Syria. The provision of aid to some 2.5 million people depends on the opening of the Bab al-Hawa border crossing in north-west Syria but the aid mechanism officially expired on Sunday after the United Nations Security Council was unable to agree on an extension. Russia vetoed a draft resolution in the UN body on Friday that proposed an extension for another year. A counter-resolution by Russia, according to which the Bab al-Hawa border crossing should remain open for six months, also failed to find a majority.