San Francisco, Aug 13 : Facebook has delayed its return-to-office plans till early next year, as the US witnesses a surge in cases of the delta variant of Covid-19. Earlier this month, Facebook had said that it would require its US employees to be vaccinated against Covid-19 when they return to the office. "Data, not dates, is what drives our approach for returning to the office. Given the recent health data showing rising Covid cases based on the Delta variant, our teams in the US will not be required to go back to the office until January 2022," a company spokesperson told The Verge on Thursday. "We expect this to be the case for some countries outside of the US, as well. We continue to monitor the situation and work with experts to ensure our return to office plans prioritise everyone's safety," the spokesperson added. Microsoft has also pushed its full office reopening date from September to "no earlier than October 4, 2021", as the Covid cases rise in the US. Twitter has shut offices in US, and Google and Alphabet CEO Sundar Pichai said the company will require employees to be vaccinated before returning to the office in the later part of the year. Amazon has also announced to delay its return-to-office timeline by January 2022. The e-commerce giant told warehouse employees in the US to once again wear masks at work, as the Delta variant is spreading fast in the country. The company said masks are now mandatory regardless of vaccination status. The US continues to be the worst-hit country with the world's highest number of cases and deaths at 36,305,005 and 619,098, respectively. /IANS