Moscow-based security company Kaspersky Lab has denied working with Russian intelligence agencies, following US media and government suspicion.
News website Bloomberg said it had seen emails showing Kaspersky had developed tools for Russia's intelligence agency.
And, on Tuesday, the US government's General Services Administration removed Kaspersky Lab from a list of approved vendors.
But the company has now insisted it has "no ties to any government".
Kaspersky Lab is known for its anti-virus software and provides cyber-security products to businesses.
Bloomberg reported it had seen emails between chief executive Eugene Kaspersky and senior Kaspersky staff, outlining a secret cyber-security project apparently requested by the Russian intelligence service FSB.
In the emails, which Kaspersky Lab confirmed were genuine, Mr Kaspersky describes tools to "protect against attacks" and also engage "active countermeasures".
Bloomberg suggested that the tools not only deflected cyber-attacks, but also captured information about the hackers launching them, to pass on to Russian intelligence services.
In the emails, Mr Kaspersky said the software could one day be sold to corporate customers worldwide.
The US General Services Administration said it had removed Kaspersky Lab from its list of government-approved suppliers "after review and careful consideration".
But, in a statement, Kaspersky Lab said: "The company has never helped, nor will help, any government in the world with its cyber-espionage efforts.
"Kaspersky Lab believes it is completely unacceptable that the company is being unjustly accused without any hard evidence to back up these false allegations."
In the statement, Mr Kaspersky offered to meet US government officials and provide his company's software code for audit.
"Kaspersky Lab, a private company, seems to be caught in the middle of a geopolitical fight where each side is attempting to use the company as a pawn in their political game," the company said.
The Trump administration has been fighting allegations that it had contact with Russian officials during the US election in 2016.