Police tonight battled two men armed with guns and explosives outside Boston, just hours after an MIT police officer was shot and killed in Cambridge. A witness cited "constant gunfire" during the Watertown standoff with dozens of cops; amid the shooting, the men threw a large bomb toward police before it exploded, the witness, a local resident, tells the New York Times. After one of the men ran toward police, he was tackled, but his fate was unclear; police were later questioning a handcuffed man in an ambulance, the Boston Globe notes.
The other man fled in a black SUV that "went right through the cops," the witness said. The men left "a few backpacks" on the scene, "and there is a bomb robot out there now," he adds. FBI agents were in Watertown, the Globe reports. The agency says it's "too early to speculate" whether tonight's incidents were tied to the marathon attacks. One of the Watertown suspects looked to be in his 20s. The nearby MIT shooting, meanwhile, prompted a manhunt in the area, and students and staff were told to stay indoors. (Read more Boston stories.)