FBI interviews employees of Russian software firm raising security concerns in US: Source

— -- Pressing ahead with a long-running investigation of a Russian software company whose products are used widely across the United States, the FBI on Tuesday interviewed several employees of the firm, Kaspersky Lab, a source familiar with the matter told ABC News.

As ABC News was first to report more than a month ago, based on sources familiar with the investigation, the FBI has recently been taking new steps to assess Kaspersky Lab’s relationship with Russian intelligence services.

Current and former U.S. officials worry that state-sponsored hackers could try to exploit Kaspersky Lab’s anti-virus software to steal and manipulate users’ files, read private emails or attack critical infrastructure in the United States -- and they point to Kaspersky Lab executives with previous ties to Russian intelligence and military agencies.

For years, such concerns have been communicated only behind closed doors and in secret memos. In February, the Department of Homeland Security issued a secret report on the matter to other government agencies. And two months ago, the Senate Intelligence Committee sent a secret memorandum to Director of National Intelligence Dan Coats and Attorney General Jeff Sessions, demanding that they address “this important national security issue.”

But the issue was brought into public view in recent months by key members of the Senate Intelligence Committee, who began asking questions about Kaspersky Lab during open hearings on worldwide threats.

Just two weeks ago, Sen. Tom Cotton, R-Ark., proposed legislation that would impose substantial sanctions on Kaspersky Lab and its employees, including freezing its business inside the United States and blocking Kaspersky Lab's foreign employees from even entering the country. That proposal didn't move forward.

Speaking about Kaspersky Lab during a Senate hearing weeks earlier, Sen. Joe Manchin, D-W.Va., said: “We are very much concerned about this, very much concerned about the security of our country."

The company has repeatedly insisted it poses no threat to U.S. customers and would never allow itself to be used as a tool of the Russian government.

"As a private company, Kaspersky Lab has no ties to any government, and the company has never helped, nor will help, any government in the world with its cyberespionage efforts,” Kaspersky Lab said in a statement issued after the first ABC News report. "The company has a 20-year history in the IT security industry of always abiding by the highest ethical business practices, and Kaspersky Lab believes it is completely unacceptable that the company is being unjustly accused without any hard evidence to back up these false allegations.

"Kaspersky Lab is available to assist all concerned government organizations with any ongoing investigations, and the company ardently believes a deeper examination of Kaspersky Lab will confirm that these allegations are unfounded," the statement added.

In fact, the FBI and other agencies in the U.S. intelligence community have yet to publicly present any evidence connecting company executives with Russian security services.

"For 20 years, Kaspersky Lab has been focused on protecting people and organizations from cyberthreats, and its headquarters' location doesn't change that mission," Kaspersky Lab said in its statement. "[J]ust as a U.S.-based cybersecurity company doesn’t allow access or send any sensitive data from its products to the U.S. government, Kaspersky Lab products also do not allow any access or provide any private data to any country's government."

In an interview with ABC News, Eugene Kaspersky said, "My response if I’m asked to spy on anyone coming from any state, any government -- not only Russian -- will be definite 'no.'"

Products from Kaspersky Lab are embedded in homes, businesses and government systems throughout the United States.

An ABC News investigation found that -- largely through outside vendors -- Kaspersky Lab software has been procured by such federal agencies as the U.S. Bureau of Prisons, the Consumer Product Safety Commission and even some segments of the Defense Department.

Kaspersky Lab is world-renowned not only for its antivirus software but also for its analysis of new and emerging threats. On Tuesday -- the same day some of its employees were being interviews by FBI agents -- Kaspersky Lab was cited in news accounts around the world for its take on a "ransomware" attack spreading around the globe.