WASHINGTON (AP) The White House said Tuesday it is preparing additional major sanctions on Russia in response to opposition leader Alexei Navalnys death last week in an Arctic penal colony.

National Security Adviser Jake Sullivan said the sanctions, on the eve of the two-year anniversary of Russias invasion of Ukraine, will be a substantial package covering a range of different elements of the Russian defense industrial base, and sources of revenue for the Russian economy that power Russias war machine, that power Russias aggression, and that power Russias repression.

National Security Council spokesman John Kirby said the U.S. had not determined how Navalny had died, but insisted that the ultimate responsibility lay with Putin.

Regardless of the scientific answer, Putins responsible for it, he told reporters.