LONDON -- Russia overnight launched a heavy air attack on Ukraine -- including striking Kyiv with drones and ballistic missiles -- that killed at least six people, including two children.

Belgium, in particular, has been reluctant to back using the frozen assets, as it is nervous about having to shoulder any potential consequences should Russia legally challenge Euroclear, the clearing house where the money is located.

Russia launched a large-scale air attack on Ukraine early Wednesday, causing power outages across most of the country, setting homes ablaze and killing at least six people, including a six-month-old baby,

A key figure in Ukraine's 3-month-old campaign to outfox its larger enemy by targeting oil facilities deep inside Russia with drones said Moscow was improving its ability to intercept them, but that his unit was forging technology to keep one step ahead.

European Union officials want to make a large loan to Ukraine backed by Russian state assets, but on Thursday, they deferred any clear decision on that plan to December.

Belgian Prime Minister Bart De Wever insists that his European partners must share the risk of using billions of dollars in frozen Russian assets that are held in his country to help keep Ukraine’s economy and war effort afloat in coming years.

Ukraine has never used American weapons to strike distant targets on Russian territory. Various long-range weapons have been used in the temporarily occupied territory of Crimea and in the east of the country.

By Dmitry Antonov, Pavel Polityuk and Simon Johnson MOSCOW/KYIV/LINKOPING, Sweden (Reuters) -Russia said on Wednesday it had carried out a major training exercise involving nuclear weapons, a day after the United States announced a delay in plans for a second summit between presidents Vladimir Putin and Donald Trump on the war in Ukraine.