WASHINGTON — President Biden ordered a sweeping review on Thursday of American intelligence about Russia’s role in a highly sophisticated hacking of government and corporate computer networks, along with what his spokeswoman called Moscow’s “reckless and adversarial actions” globally and against dissidents inside the country.
At the same time, White House officials said the president would seek a clean, five-year extension of the last remaining nuclear arms treaty between the two countries, which expires in two weeks.
“This extension makes even more sense when the relationship with Russia is adversarial as it is at this time,” said Jen Psaki, the White House press secretary.
Taken together, the paired announcements make clear the complexity of Mr. Biden’s two-step approach to contain the actions of President Vladimir V. Putin of Russia.
Mr. Biden’s order for a study of the SolarWinds hacking — named for the Texas company whose widely used network management software was one way Russian hackers gained access — comes as intelligence officials have quietly concluded that more than a thousand Russian software engineers were most likely involved in it, according to people involved in the investigation.