Four separate shootings left two men dead and five other people injured during a stretch of violence in Boston on Friday, according to authorities.

The two fatal shootings, the first happening in Roxbury just after 1:30 a.m. and the second in Mattapan shortly after 12:20 p.m., came hours after Fourth of July celebrations. Four additional people were injured in two other shootings, police said.

The city’s number of fatal shootings for the year jumped a third to six with the two deadly incidents, city police figures show.

“Coming into the holiday, we have a strategic plan,” said police Superintendent Felipe Colon, head of BPD’s Bureau of Investigative Services, “and we have areas that we are concerned about, we have officers in those areas. Again, it’s been an active 24 hours, and we will continue to monitor those areas.”

In the latest shooting, police responded to the area of Gladeside Avenue and Donwood Terrace in Mattapan for a report of a person shot at about 12:23 p.m., Colon said. On arrival, officers found a man and woman beside a motor vehicle suffering from gunshot wounds, he said.

Both victims, whom authorities are working to determine their ages and identities, were taken to local hospitals. The female is suffering from injuries that Colon said are not life-threatening, while the man has died.

Colon added that police had yet to identify a suspect or person of interest, with officers actively investigating the violence.

“Preliminary reports indicate this is not a random attack,” he said, “but as always we are asking the public for their help.”

Officers assigned to the South End responded to the first deadly shooting of the day at roughly 1:33 a.m., in the area of 618 Shawmut Ave., in Roxbury. They found a man suffering from gunshot wounds that he’d later die from at a local hospital, police said in a statement.

That shooting came mere minutes after police received a report of gunfire in the area of 297 Centre St. in Jamaica Plain at 1:26 a.m. Officers found three adult victims with gunshot wounds, and emergency responders took them to hospitals for treatment of injuries considered not life-threatening, according to police.

The violence did not end there, with officers responding to another shooting in Dorchester in the area of 783 Blue Hill Ave., at about 5:18 a.m. At least one victim in that incident was taken to the hospital with life-threatening injuries.

Authorities did not immediately say whether the shootings were connected.

Before this stretch of violence, Boston had recorded four fatal shootings this year, a drastic decrease from the 15 at this time last year, city police figures show.

Mayor Michelle Wu, speaking to Boston 25 at an event at City Hall Plaza Friday morning, called the shootings “unacceptable.”

“My heart is with those who are recovering and those who are grieving today,” the mayor said. “We have seen some tremendous progress and trending in the right direction in terms of violence across the city this year and this week and this weekend is always one that we are on high alert on because there are so many people out and about and unfortunately, we still have a lot more work to do.”

Officials are urging anyone with information on the shootings to contact the Boston Police Homicide Unit at 617-343-4470. Community members wishing to be anonymous can call the CrimeStoppers Tip Line at 1-800-494-TIPS or by texting the word “TIP” to CRIME (27463).