Department of Veterans Affairs Secretary Robert McDonald struggled to answer questions Thursday about the number of employees he has fired since taking the helm of the agency in July 2014 amid scrutiny over the perceived lack of accountability at the VA.

During a hearing before the Senate Veterans Affairs Committee Thursday, McDonald told lawmakers he had fired more than 2,600 employees in his time at the agency.

But in a letter to the editor of the Wall Street Journal published just one day earlier, McDonald said his agency had fired 2,400 employees in the past 18 months.

That number has fluctuated in recent months depending on who is talking and where, casting further doubt on the VA's stated commitment to rooting out employees who break the rules.

For example, Sloan Gibson, the VA's deputy secretary, told the House Veterans Affairs Committee in December that 869 employees has been terminated in 2015.

A month earlier, McDonald had boasted to a luncheon audience at the National Press Club that 1,500 people had been fired in 2015.

Congress and the public began putting pressure on the VA to hold its officials more accountable in 2014, when the agency's inspector general confirmed whistleblowers' claims that veterans had died while waiting long stretches of time to see a VA doctor. The watchdog even discovered VA workers had covered up the delays by creating fake patient waiting lists at 110 facilities across the country.

To date, just three employees have been fired for their involvement in the nationwide wait time manipulation scheme.

VA leaders have fought against legislation that would remove some of the barriers to firing agency employees, arguing such measures would unfairly single out the VA over other government agencies.

In the meantime, VA employees accused of stealing money from the government and others found guilty of posting veterans' confidential medical information on social media have kept their jobs.

McDonald told lawmakers during a field hearing in August he had terminated more than 140,000 employees for disciplinary reasons.

But the VA secretary walked that figure back dramatically just a few minutes later after a lawmaker pressed him on whether his agency had truly dismissed so many employees.

"The actual number of fired is 1,800," McDonald said later in the hearing.

McDonald, who worked as CEO of Procter & Gamble before shifting to the VA, admitted during the hearing that he had an easier time firing employees in the private sector than he has had at the VA.

"You cut a deal with the employee and you're able to buy them out," McDonald said of the reason why firing personnel at a private company is easier than firing a government employee.

However, VA employees are sometimes given generous settlements in exchange for leaving their positions, such as a hospital director who was paid $86,000 to resign amid allegations of whistleblower retaliation, according to a Monday report from the Daily Caller.

Another VA hospital director was paid $75,000 to retire in Oct. 2013 during an investigation into the avoidable deaths of nine veterans at the facility she oversaw.

Regardless of the exact figure cited as the number of employees fired, McDonald has often framed it as evidence of his team's tough stance on misconduct in the wake of the wait time scandal.

But former VA Secretary Eric Shinseki fired nearly as many employees in the last full year of his tenure, which was before the wait time scandal forced him to resign in 2014.

Under Shinseki, the VA removed 2,247 employees for misconduct in 2013 alone, according to data from the Office of Personnel Management.

McDonald said Thursday he had fired 2,600 in his entire stint as VA secretary, and that number has at times been reported as even lower.

The VA did not return a request for comment as to how many officials have actually been removed for misconduct since McDonald entered office.