The FBI announced today it was investigating the embarrassing hack of Democratic National Committee emails -- a breach the Clinton campaign blamed on Russia, accusing Moscow of seeking to influence the US presidential election.
The emails leaked by WikiLeaks, which reveal that party leaders sought to undermine the campaign of Hillary Clinton's rival Bernie Sanders, threw the Democratic National Convention into disarray on its first day and prompted the party boss to resign.
While a series of experts pointed the finger at Moscow, others urged caution. Russia denied any involvement.
"The FBI is investigating a cyber intrusion involving the DNC (Democratic National Committee) and are working to determine the nature and scope of the matter," the agency said, making no mention of possible culprits.
"A compromise of this nature is something we take very seriously, and the FBI will continue to investigate and hold accountable those who pose a threat in cyberspace."
Both the White House and the State Department deferred to the FBI on whether Russia was to blame, but highlighted that cybersecurity has been an ongoing issue of concern between Washington and Moscow.
"We know that there variety of actors both state and criminal who are looking for vulnerabilities in the cyber security of the United States and that includes Russia," White House spokesman Josh Earnest said.
State Department spokesman John Kirby added: "I think we need to let the FBI do their work before we try to form any conclusions here about what happened and what the motivation was behind it."
Russian Foreign Minister Sergei Lavrov batted away any suggestion that Moscow was behind the hack. He spoke ahead of a meeting Tuesday with US counterpart John Kerry in Laos.
Lavrov, in the Laos capital Vientiane for a regional security forum, shrugged when asked by reporters if Russia was responsible.
"Well I don't want to use four letter words," he said cryptically, before greeting Kerry with a handshake.
Kerry said later, after his talks with his Russian counterpart: "With respect to Foreign Minister Lavrov, I did raise the issue of DNC. As you know the FBI is investigating the incident and it's important for the FBI to do its work before we draw any conclusion."
But Clinton's team -- looking to tamp down an internal party uproar just days before she becomes the first woman in US history to be formally conferred the presidential nomination by a major party -- was quick to point fingers.
