Boston:
Two young men, armed with guns and explosives in what appeared to be backpacks, engaged in a violent standoff with dozens of police on a street in Watertown, Mass., Thursday night, police and residents said.
At around 1 a.m., two residents said they heard what sounded like firecrackers going off. When they looked out of their windows, they saw two young men taking cover behind a black Mercedes sports utility vehicle, in a shootout with dozens of police about 70 yards away. A police spokesman said there was a strong possibility that the incident was linked to the fatal shooting of a campus police officer at the Massachusetts Institute of Technology. The chaos that descended on the residential streets came as the community was still reeling from Monday's bombings at the Boston Marathon that killed three and wounded more than 170.
Andrew Kitzenberg, 29, said he looked out of this third-floor window to see two young men of slight build in jackets engaged in "constant gunfire" with police officers. A police SUV "drove towards the shooters," he said, and was shot at until it was severely damaged. It rolled out of control, Kitzenberg said, and crashed into two cars in his driveway.
The two shooters, he said, had a large and unwieldy bomb.
"They lit it, still in the middle of the gunfire, and threw it. But it went 20 yards at most."
It exploded, he said, and one of the two men ran toward the gathered police officers. He was tackled, but it was not clear if he was shot, Kitzenberg said.
The explosions, said Loretta Kehayias, 65, another resident, "lit up the whole house. I screamed. I've never seen anything like this, never, never, never."
Meanwhile, the other young man, said Kitzenberg, got back into the SUV, turned it toward officers and "put the pedal to the metal."
The car "went right through the cops, broke right through and continued west."
The two men left "a few backpacks right by the car, and there is a bomb robot out there now."
Police had told residents to stay away from their windows, he said.
A police spokesman, Dave Procopio, told reporters that one suspect was being taken to an area hospital and another is "on the loose." Explosives were involved, he confirmed, and bomb disposal units were active. When asked about links to Monday's bombings at the Boston Marathon, he said, "We're investigating that, and the FBI is investigating that."
At least two people were being taken from the scene in ambulances, said a resident who declined to give his name.
The standoff came days after two bombs had exploded at the Boston Marathon, killing three and injuring more than 170. There was speculation that the two incidents were linked but, amid the chaos early Friday morning, there was no confirmation of that. The FBI released new images of the men early Friday as part of a campaign to try and identify them.
The incident in Watertown came just minutes after a third explosion of violence in Boston - a campus police officer was shot and killed at the Massachusetts Institute of Technology.
The officer, who was not named, responded to a report of a disturbance, Middlesex County District Attorney Michael Pelgro said in a statement early Friday. He was found, the statement said with "multiple gunshot wounds" and taken to Massachusetts General Hospital where he was pronounced dead.
At the campus, helicopters whirred overhead, and police cars dotted through the streets. A crime scene was cordoned off, and at least one dog unit was on the scene.