Russian President Vladimir Putin has said he is making "maximum effort" to avert a global food crisis after Russia's withdrawal from a deal that enabled grain export from Ukraine. We are taking maximum efforts to avert a global food crisis,” Mr Putin said. He was speaking during the opening of a two-day Russia-Africa summit in St Petersburg, with 17 heads of African states in attendance. We intend to further develop it," Mr Putin said in a welcome letter to participants of the summit. Mr Putin is expected to conduct bilateral talks with his counterparts on the sidelines and will deliver an address at the plenary session.