STORY: The U.S. government has been warning American firms to be careful with anti-virus software from Russian tech firm Kaspersky.

That’s according to a senior U.S. official and two other Reuters sources.

The classified briefings were reportedly part of a Washington move to prepare critical infrastructure providers for possible cyber-attacks.

Moscow-based Kaspersky was founded by former Russian intelligence officer Eugene Kaspersky.

It makes some of the most popular anti-virus software.

In a statement, a company spokeswoman said the U.S. comments were not appropriate or just.

Speaking back in 2017, Kaspersky himself was adamant his firm would not collude with spies:

"Never and if the Russian government comes to me and asks me to do anything wrong, or my employees I will move the business out of Russia.”

A U.S. official said Washington feared Kaspersky staff could be pressured into providing access to customers’ computers.

On March 25, the Federal Communications Commission added the company to its list of possible security risks.

It’s not clear whether a specific incident prompted the latest briefings.