The news comes ahead of Tottenham’s trip across the capital on Tuesday evening to face the League Two side in the Carabao Cup.
A statement on the club’s official website read: “Following our game on Saturday 19th September, COVID-19 testing was conducted on all of our first-team playing squad.
“Today (Monday 21st) we received formal confirmation which shows that a number of our first-team squad have tested positive for COVID-19.
“We have informed the EFL and Tottenham Hotspur and will make a further announcement regarding Tuesday’s match shortly.
“We have also informed Mansfield Town, Plymouth Argyle and Oldham Athletic, our three most recent opponents, prior to the public release of this information.
“Leyton Orient’s priority is the health and well-being of its players and staff. Those who have tested positive will now strictly follow government self-isolation guidelines.
“The Breyer Group Stadium and training ground facilities will be closed until further notice.
“At this time, the club will make no further comment.”
More to follow.