BOSTON — Five people were killed in four shootings in Boston and its suburbs late Wednesday and early Thursday, including a 21-year-old woman authorities believe was an unintended target, officials said.

Three young men were killed in two shootings in Boston just minutes apart Wednesday night, drawing condemnation from Mayor Marty Walsh.

“I am extremely saddened and disturbed by the violence that took place overnight in our community; this has to stop,” the mayor said in a statement.

There was no indication that any of the shootings are related. The city now has recorded 20 homicides this year, compared to 35 at this time last year.

No arrests had been announced in any of the cases by Thursday evening.

The violence began when a man was shot in a car in Cambridge near the Massachusetts Institute of Technology campus about 8:40 p.m. Wednesday. The vehicle headed toward Kendall Square, where it stopped in front of a hotel. The man, 31-year-old Rasaun Nichols of Cambridge, was taken to a hospital and pronounced dead. The driver is cooperating with investigators.

Three men were shot, two fatally, in Boston’s Roxbury section about 10:15 p.m. Wednesday. The men, both in their 20s, were pronounced dead at the hospital. Their names were not released. The third victim did not make himself known to police until about three hours later and he is expected to survive.

Just minutes later, three men attending a family gathering were shot in Boston’s Mattapan neighborhood. One died; the other two are expected to survive. The name of the deceased man was not released.

The final shooting occurred about 1 a.m. Thursday, when authorities say 21-year-old Ashlee Berryman of Malden was shot and killed outside a nearby Everett restaurant. Witnesses say she was caught in the crossfire of two shooters.

Police in all four shootings are asking witnesses to come forward.