RUSSIA warned the West that a deal allowing Ukrainian grain to be exported from the Black Sea would cease unless a United Nations agreement aimed at overcoming obstacles to Russian grain and fertiliser exports was fulfilled. The United Nations and Turkey brokered the Black Sea deal for an initial 120 days in July last year to help tackle a global food crisis that has been aggravated by Moscow's invasion of Ukraine, one of the world's leading grain exporters. Russia has repeatedly warned it will allow the deal to expire because of obstacles to its own exports of grain and fertiliser…