Ukraine set up a joint team with the European Union earlier in April to investigate alleged war crimes in Bucha.
Before Russia's invasion began in late February, an took down the websites of Ukraine's Ministry of Defense and some banks.
Ukraine isn't a member of , but neighboring Poland is.
Secretary-General António Guterres, who will then visit Kyiv.
The attack was seemingly timed to begin on April 8 and would have left two million people without power.
The Defense Security Cooperation Agency approved the potential sale and has provided the legally required notification to Congress.