The United Nations said Tuesday that "consultations" were continuing after Russia agreed to extend a vital Ukraine grain export deal, but only for a further 60 days, instead of the usual 120.

"The United Nations will do everything possible to preserve the integrity of the agreement and ensure its continuity," Jens Laerke, spokesman for the UN humanitarian agency OCHA, told reporters, adding that "the consultations... with all parties, and various levels continue."