Russia has given its clearest indication yet that it will not renew the Black Sea Grain Initiative after the United Nations’ brokered agreement is due to run out on 18 May.

Its inspectors have threatened that they will not approve vessels scheduled to leave Ukraine’s ports after that date.

In documents seen by news agency Reuters, Russia said the ship registration will only take place “after receiving guarantees from shipowners to complete their participation in the initiative” by 18 May.