Americans can order four more free COVID-19 tests through the mail, starting on Thursday. It's part of the Biden administration's plan to deal with an increase in COVID cases sparked by indoor holiday gatherings.

The tests can be ordered on COVIDtests.gov and will start to ship the week of Dec. 19, a senior administration official told reporters on a conference call. The government is urging people to test themselves when they have symptoms, and before visiting with family.

It's the fourth round of free rapid tests this year. The White House had suspended the program in September and said that it would not be able to send out more kits because Congress denied requests for more funding for the program. But the administration shuffled around funds to buy more of the tests for the national stockpile, the official said.

"We know that the virus will circulate more quickly and easily as folks gather indoors for the winter holiday season," the official said, speaking on condition of anonymity. Officials saw cases increase after Thanksgiving, and anticipate that there could be another uptick after December holiday celebrations.

Tests are also available at community testing sites, food banks and schools, and through Medicare. People covered by private health insurance plans can get fully reimbursed for eight tests per month.

The federal government is trying to make it easier for Americans to get vaccines, tests and COVID treatments like Paxlovid during the winter months. It is staging supplies like ventilators as well as personal protective equipment, and wants to help states set up mobile and pop-up vaccination sites.

The government has a particular focus on nursing homes and long-term care facilities, and wants to work to vaccinate residents with the latest booster shot, and offer Paxlovid to people who get the virus.

"We are a few years into this pandemic, and we are prepared for this moment," the official said.