UN Secretary-General Antonio Guterres tells reporters that controversial cluster munitions pledged by the United States to Ukraine "must not be used on the battlefield" as a result of the risk to civilians their use poses after a conflict is over. Speaking to the press following a meeting with Belgian Prime Minister Alexander de Croo, Guterres says that whilst he understands that neither Russia, the United States or Ukraine are party to the 2008 Oslo convention banning cluster bombs, the UN chief considers the convention "a very important instrument" and that he "stands by" his opposition to their use. IMAGES AND SOUNDBITES