(Reuters) -Amazon.com will require employees to return to working at company offices five days per week beginning next year, toughening a prior three-day mandate.

The change is necessary to "invent, collaborate and be connected" wrote CEO Andy Jassy in a letter to employees on Monday posted to its website. He said the experience of a three-day mandate "strengthened our conviction about the benefits" of in-office work.

Companies have been allowing many employees to work from home since the pandemic, leaving downtown offices nearly empty in a number of cities such as San Francisco and Seattle. However, some tech firms are beginning to mandate employees to return to their offices two or three days per week.

Amazon has taken a tougher stance than many of its rivals as COVID-19 has become less of a daily threat. Employees have described to Reuters how Amazon has required them to report to, in some cases, distant offices or move to Seattle to keep their jobs.

And some employees who were consistently out of compliance with the existing three-day mandate were told they were "voluntarily resigning," and were locked out of Amazon's systems. A spokesperson for Amazon did not immediately respond to say whether the new mandate will be as stringent, nor did an employee Q&A shared with Reuters on Monday make it clear.

The mandate has been deeply unpopular among a vocal group of employees who have said working from home is both effective and spares time and money for commuting. In May last year, workers at Amazon's Seattle headquarters staged a walkout protesting changes to the e-commerce giant's climate policy, layoffs and a return-to-office mandate.

As part of an organizational restructuring, Amazon is looking to increase the ratio of individual contributors to managers by at least 15% by the end of the first quarter of 2025. In the Q&A, Amazon said some "some organizations may identify roles that are no longer required" without giving additional details.

Amazon also is eliminating a prior program that allowed workers the option to work from anywhere for four months per year, according to the Q&A.