WASHINGTON (Reuters) - Eugene Kaspersky, the co-founder and chief executive of Moscow-based anti-virus firm Kaspersky Lab, said on Thursday he accepted an invitation to testify to U.S. lawmakers later this month over the security of his company’s products, but that he needed an expedited visa in order to do so.

The appearance before Congress would be Kaspersky’s most high-profile attempt to address long-standing accusations that his firm may be conducting espionage on behalf of the Kremlin.

The testimony would also provide a rare public airing of the tensions in cyberspace between the United States and Russia, as Kaspersky Lab has argued it has been caught in a proxy battle over broader tensions between the two countries.

U.S. intelligence agencies have concluded that Russian President Vladimir Putin ordered a multipronged digital influence operation last year in an attempt to help Donald Trump win the White House, a charge Moscow denies.

In an email to Reuters, Kaspersky said, “I appreciate and accept the invitation to testify before the U.S. House of Representatives Committee on Science, Space, and Technology, and if I can get an expedited visa, I look forward to publicly addressing the allegations about my company and its products.”

The invitation came a day after the Trump administration told U.S. government agencies to remove Kaspersky Lab products from their networks, saying it was concerned the company was vulnerable to Russian government influence and that using its anti-virus software could jeopardize national security.

The committee said it invited Kaspersky to testify on Sept. 27. U.S. government and private-sector cyber experts were also invited.

Fears about Kaspersky Lab have metastasized in recent months as U.S. lawmakers and intelligence officials have tried to understand the full range of Russia’s cyber-enabled meddling in the 2016 presidential election.

The Russian embassy in the United States called the Kaspersky Lab ban “regrettable” and said it delayed the prospects of restoring bilateral ties.

It said the move was part of a series of steps that would detract from mutual priorities, such as fighting terrorism, and that the United States should reconsider Russia’s proposal to set up a joint cyber security group - an idea Trump has entertained but that Republicans and Democrats widely panned.

‘WHATEVER IT TAKES’

In an opinion piece published by Forbes on Thursday, Eugene Kaspersky defended his company, which he said had been targeted for nearly five years by unsubstantiated rumors that have yielded no proof of any wrongdoing.

“I’ve repeatedly offered to meet with government officials, testify before the U.S. Congress, provide the company’s source code for an official audit and discuss any other means to help address any questions the U.S. government has about Kaspersky Lab - whatever it takes, I will do it,” Kaspersky wrote.

But Kaspersky told NBC News in July that he was not currently traveling to the United States because he was “worried about some unexpected problems” if he did, citing the “ruined relationship” between Moscow and Washington.

Kaspersky Lab did not immediately respond when asked when its chief executive was last in the United States. A source familiar with U.S. inquiries into the company said he had not been to the United States since spring of 2015.

Two sources familiar with the inquiries said Kaspersky has been most concerned about the probe of allegations that the company sabotaged competitors in the anti-virus industry through information-sharing programs. (reut.rs/2wdhCBi)

Also on Thursday, the U.S. Senate came a step closer to passing legislation that would codify the Trump administration’s ban, voting to expand an amendment to a pending defense policy spending bill to prohibit both federal civilian and military agencies from using Kaspersky Lab products.