The United States Tennis Association (USTA) said it had made the decision not to allow spectators to attend the qualifiers to "ensure the health and safety of all".

Matches are scheduled to be held in the week before the main tournament, the fourth and final tennis Grand Slam of the year, begins on August 30.

According to the USTA, more than 2,500 people, including athletes, their team and other personnel, will be on site during the qualifying week at Flushing Meadows.

"This was a particularly tough decision for the USTA to make, given the immense popularity of US Open qualifying among fans," the USTA said in a statement.

"But after consulting with local health authorities and the US Open medical team, it was determined that it was the right decision to ensure the health and safety of all."

Organisers said in June that fans will be permitted at the main competition, making it the first Grand Slam to be held with a full capacity crowd since last year's Australian Open.

Indoor capacity at the USTA Billie Jean King National Tennis Center within Flushing Meadows has been reduced because of COVID-19.

Some players' facilities have also been moved outdoors during qualifying as part of efforts to reduce the risks posed by the novel coronavirus.

"With that, there is not enough room to allow fans to access the site while still ensuring player and fan safety - which remains our top priority," the USTA said.

Japan's Naomi Osaka and Austria's Dominic Thiem are the defending women's and men's US Open champions, respectively.