San Francisco, Aug 3 : Facebook has asked all its employees in the US to wear masks at offices as the country witnesses a surge in covid cases. The new mask-wearing police went into effect from August 3 will remain in place until further notice. "Given the rising numbers of Covid cases, the newest data on Covid variants, and an increasing number of local requirements, we are reinstating our mask requirement in all of Facebook's US offices, regardless of an employee's vaccination status," a Facebook spokesperson told The Verge. Facebook said last week that it would require its US employees to be vaccinated against Covid-19 when they return to the office. "As our offices reopen, we will be requiring anyone coming to work at any of our US campuses to be vaccinated," Facebook's vice president of people Lori Goler had said. The Covid-19 cases have increased in the US, even as vaccination rates grow amid concern over the highly contagious Delta variant. The US Centers for Disease Control and Prevention (CDC) said that there were about 72,000 new cases per day. Barely three months after suggesting that vaccinated people no longer needed to wear masks, indoors or out, the US CDC has now recommended people to resume wearing masks amid the surging delta variant. Other tech companies also took cognizance of the new CDC guidelines. 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. Apple now requires customers and staff at most of its more than 270 US retail stores to wear masks even if they are vaccinated. /IANS