This story was updated at 2 p.m.

Since Aug. 6, when the University of Massachusetts began regular asymptomatic of its students and staff, no single day had yielded more than 35 positive tests. Until this week.

In the first three class days of the spring semester, the school recorded 239 positive tests — 36 on Monday, 103 on Tuesday, 100 on Wednesday — shattering the single-day case record and sending the positive test rate to 2.9 percent.

In a Friday morning email to the UMass community, Executive Director of Environmental Health and Safety Jeffrey Hescock and Public Health Director Ann Becker said transmission of the virus had been “especially prevalent among some undergraduate students not following social distancing and mask protocols in social or residential settings, both on and off campus.”  Of the cases, 233 are from students, campus spokesperson Ed Blaguszewski told the Daily Collegian via email.

Hescock and Becker’s email also announced that the University would be increasing its “Operational Posture,” a measure of the seriousness of virus transmission that influences decision making, to “Elevated,” the second highest of four levels.

The “Elevated” designation means a ban on student gatherings “of any size,” both on- and off-campus, will go into effect. Additionally, the school will halt in-person activities at Recreation Center and in-person dining, place additional restrictions on building access, and close campus to all visitors (excluding the testing centers).

There are currently 328 active cases between students, staff and faculty, according to the school’s testing dashboard. Roughly two-thirds of on-campus quarantine and isolation space remains open.

Hescock and Becker’s email noted that there is no evidence of case spread from in-person classes or any indication of increased spread between students and staff.

This story will be updated as more information becomes available.

Will Katcher can be reached at [email protected]. He can be followed at @will_katcher.