According to Twitter executives, an increasing number of employees are leaving the company with an 18.3% staff reduction.

Employee departures are putting Twitter in a tense position as the company faces several challenges, including its legal battle with Elon Musk and the whistleblower claims of its former security chief.

Twitter executives briefed employees about the departures during a company-wide meeting. Parag Agrawal, the company’s chief executive, also issued a disclaimer on the claims of former security chief Peiter “Mudge” Zatko. According to Agrawal, Zatko’s allegations were “foundationally, technically and historically inaccurate.”

Zatko accused Twitter of falsely claiming that it has a robust security plan and making misleading statements about its defenses against hackers and spam accounts.

According to Zatko’s spokesman, the whistleblower has already discussed his complaints with staff of the chairman and senior members of the Senate Judiciary Committee, the House Energy and Commerce Committee and the Senate Intelligence Committee.

Zatko will discuss his allegations before the U.S. Senate Judiciary committee on September 13.

Twitter will also have to contend with Tesla billionaire Elon Musk in court in October for his decision to opt out of his $44 billion offer to buy the company.

The sources for this piece include an article in Reuters.