Washington, Nov 14 (IANS): The US Postal Service (USPS) has recently raised concerns over new vaccination rules announced by the federal government.

Compliance "could result in labour challenges and high levels of absenteeism", the 644,000-employee USPS wrote in a financial filing.

Some employees could opt to leave, which "could cause significant business disruptions, and could adversely impact service performance and result in lower mail volume and revenue", Xinhua news agency quoted the filing as saying.

The federal government earlier this month asked companies with 100 or more employees to mandate weekly testing or vaccines by January 4, while it required healthcare workers at facilities participating in Medicare and Medicaid to be fully vaccinated.

The new rules cover 84 million employees in the US, according to government officials.

According to a Gallup poll released in September, 56 percent of Americans favour vaccine mandates at their office or work site.

At the same time, however, many US workers strongly oppose vaccine mandates.