State officials announced Wednesday that Boston had moved into the red zone for coronavirus risk and that the city and 28 other communities would not advance into the next stage of the state’s reopening plan on Monday.
Boston is one of 23 cities and towns designated red, meaning they have had more than 8 cases per 100,000 residents in the past 14 days, the Department of Public Health reported, as the death toll from confirmed coronavirus cases in Massachusetts rose by 32 to 9,242.
The number of confirmed cases of the virus climbed by 510, bringing the total to 129,753, officials said.
Governor Charlie Baker announced Tuesday that lower-risk communities can reopen some businesses as the state moves into Step 2 of Phase 3 on Monday. The state has been in a holding pattern at Step 1 of Phase 3 since the summer.
Lower-risk communities are defined as cities and towns that have not been a red COVID-19 spread community in any of the last three Department of Public Health weekly reports.
Nearly 30 of Massachusetts' 351 cities and towns that are or have been in the red category will be excluded from moving into Step 2, according to Wednesday’s weekly community update.
The communities excluded from proceeding are Attleboro, Avon, Boston, Chelsea, Dedham, Dracut, Everett, Framingham, Haverhill, Holliston, Lawrence, Lowell, Lynn, Lynnfield, Marlborough, Methuen, Middleton, Monson, Nantucket, New Bedford, North Andover, Plainville, Revere, Saugus, Springfield, Tyngsborough, Winthrop, Worcester, and Wrentham.
Most of the 29 communities on the list are currently in the red category, but six towns are not: Dedham, Monson, Plainville, Saugus, Tyngsborough, and Wrentham.
At a City Hall briefing earlier Wednesday, Mayor Martin J. Walsh said positive COVID-19 cases had recently ticked up, and Boston would not be moving forward with Step 2 of Phase 3.
Speaking during his regular briefing at City Hall, Walsh said the seven-day average for positive tests in Boston for the week ending Sept. 26 was 3.5 percent, up from 2.2 percent the week before.
State officials also reported Wednesday that 14,404 more people had been tested for coronavirus, bringing the total to more than 2.23 million. The number of tests administered climbed to more than 4.05 million. The state also reported that new antibody tests had been completed for 285 people, bringing that total to 120,418.
The seven-day average rate of positive tests, which is calculated from the total number of tests administered, remained at 1 percent for a second day, after ticking up in Tuesday’s report. The lowest observed figure for that metric — a number watched closely by state officials — is 0.8 percent.
The daily percentage of individuals whose tests for COVID-19 come back positive has surpassed 3 percent twice in recent days, more than tripling from a low of 0.9 percent a month ago. On Tuesday, the latest day for which data is available, that rate was 2.8 percent, according to the state numbers released Wednesday.
Meanwhile, the three-day average of hospitalized coronavirus patients grew slightly from 423 to 433 in Wednesday’s report. The lowest that metric has been is 302.
The number of hospitals using surge capacity jumped to six, after hovering at two for the past week, and the three-day average of deaths from confirmed cases dropped from 16 to 15; the lowest that number has been is nine.
Travis Andersen and Dasia Moore of the Globe staff contributed to this report.