Western leaders on Sunday night set an ultimatum for Vladimir Putin as the international outcry over the treatment of bodies from Malaysia Airlines Flight MH17 led to calls for Russia to be further punished over its role in Ukraine.

During a weekend of fast-paced diplomacy, Britain, France and Germany warned the Russian president that he faced further sanctions on Tuesday unless he ensured that air accident investigators had full access to the crash site in eastern Ukraine.

Armed separatists on Sunday stacked body bags containing up to 200 victims into three refrigerated train wagons left idle at a train station in Torez, the town nearest to the crash site. Other remains were still uncollected near the plane wreckage, lying under baking summer heat.