Explosions, deaths on Boylston Street

Second explosion. Photo by Dan Lampariello.

At least two bombs exploded near the Marathon finish line around 2:50 p.m., killing two people. One was an eight-year-old boy, the Globe reports. WCVB and WBZ report scores of people are being treated at local hospitals.

The windows of Marathon Sports blew in. Every ambulance in the city was ordered in as first reponders rushed in to help people with limbs ripped off. Boston University reports one of the critically injured was a BU student.

As late as 3:30 p.m., police were continuing to find injured runners, as far away as Mass. Ave. and Commonwealth Ave.

Wounded being treated. More photos from the scene. Copyright Arturo Gossage.

Police Commissioner Ed Davis said a third explosion occurred around 4:20 p.m. at the JFK Library in Dorchester; he said investigators are not sure if it was related, but that there were no injuries. UPDATE: Police tweeted around 5:30 p.m. that the explosion there was related to a fire, but was not a bomb.

Gov. Patrick: "We've had a horrific attack here in Boston this afternoon."

Davis and Patrick urged people to stay home; WCVB reports the Bruins game tonight has been canceled.

The Marathon medical tent was pressed into service to care for the wounded.

People were urged to stay off cell phones to avoid overloading the system for emergency calls.

Bruce Mendelsohn was watching the race from his office right above Marathon Sports, posted a graphic photo of the blood-stained sidewalk, writes:

There was a primary and a secondary explosion. I ran outside to help. Blood on sidewalks & 10-12 casualties.

Police immediately shut Copley Square and began investigating a series of additional suspicious packages along Boylston Street. Businesses, bars and restaurants were evacuated from the rear; at least two apartment buildings in the Prudential Center were evacuated onto Huntington Avenue.

FBI, State Police joined the investigation.

Around 4 p.m., the BPD bomb squad blew up another suspicious device near the Copley library.

Police sent MBTA buses to Audubon Circle to ferry runners away from the scene. But that was too late for hundreds of runners who found themselves bottlenecked at Mass. and Comm. Ave.

The MBTA stopped Green Line service between Kenmore and Park, Orange Line trains were bypassing Downtown Crossing, Red Line trains were bypassing Park and Downtown Crossing. Logan Airport stopped all incoming flights. Police were stopping all people entering North Station for security checks.

Boston University and Northeastern University told their students to stay on campus.