This is a developing story. Check back for updates.
Two explosions were reported near the Boston Marathon finish line, killing at least two people, and dozens injured.
Early eyewitness reports estimate at least a dozen people were injured when two explosions occurred in downtown Boston, while the race was still ongoing.
MCI: 20-30 people injured in front of Boston Public Library after explosion at finish line of Boston Marathon— Boston_Fireman (@Boston_Fireman) April 15, 2013
Update: Explosion on marathon route at Marathon Sports store on Boylston Street; possible multiple injuries at this time.— Boston_Fireman (@Boston_Fireman) April 15, 2013
UPDATES WILL BE ADDED BELOW AS THEY COME
6:33 p.m. One of the two people killed was an 8-year-old child.
Law enforcement official confirms that one of two people killed in today's explosions was eight years old. #BostonMarathon— NBC News (@NBCNews) April 15, 2013
6:17 p.m. Speaker of the House John Boehner released a statement, and ordered Capitol flags be flown at half-staff.
Words cannot begin to express our sorrow for the families who are grieving so suddenly right now. The House of Representatives offers its prayers to the victims and the city of Boston. We also give thanks for the professionals and Good Samaritans who prevented further loss of life. This is a terrible day for all Americans, but we will carry on in the American spirit, and come together with grace and strength.
6:13 p.m. Obama: "We still do not know who did this or why. People shouldn't jump to conclusions before we have all the facts."
"Boston is a tough and resilient town. So are its people."
"I am supremely confident Bostonians will pull together.. American people will be with them every step of the way."
Pres. Obama stops short of calling the explosions acts of terrorism.— Mark Knoller (@markknoller) April 15, 2013
6:11 p.m. President Obama addresses the nation.
"On days like this there are no Republicans or Democrats – we are Americans, united in concern for our fellow citizens." —President Obama— The White House (@whitehouse) April 15, 2013
6:03 p.m. More than a thousand Boston-area residents have offered a place to stay for people stuck in town after the marathon.
5:44 p.m. President Obama will speak shortly after 6 p.m.
5: 41 p.m. CNN: Boston Police spokeswoman said no suspect is currently in custody.
5:40 p.m. Ground stop has been lifted at Logan.
UPDATE: The Federal Aviation Administration has lifted a temporary ground stop that halted inbound flights to Logan International Airport— Boston.com News (@BostonDotCom) April 15, 2013
5:34 p.m. Marathon officials said of 23,326 starters, 17,584 finished the race. Of the remaining runners, 4,496 had passed the 40 kilometer mark and were diverted away from the scene, while 1,246 did not make it to the 40 kilometer mark.
5:32 p.m. Possible suspect:
RT @nbcnews: Officials say that Boston PD are "guarding" a wounded man at a Boston hospital as a "possible suspect"— NBC Nightly News (@nbcnightlynews) April 15, 2013
5:30 p.m. More from the White House:
This afternoon, the President received briefings from FBI Director Robert Mueller and DHS Secretary Janet Napolitano on the active investigation and response to the incident in Boston, including the ongoing coordination with state and local officials.
5:28 p.m. No additional threats forthcoming.
BREAKING: No information to indicate there are any additional threats following these explosions, U.S. officials tells NBC News— NBC Nightly News (@nbcnightlynews) April 15, 2013
5:27 p.m. Injury count now likely around 100.
MARATHON EXPLOSIONS: Two killed, at least 90 injured in Boston Marathon finish line explosions; third blast reported at JFK Library— The Boston Globe (@BostonGlobe) April 15, 2013
5:25 p.m. Boston police say JFK Library incident appears unrelated coincidence.
Reports of Marathon Runners that crossed finish line and continued to run to Mass General Hospital to give blood to victims #PrayforBoston— NBC Sports Network (@NBCSN) April 15, 2013
5:05 p.m. Tonight's Bruins game at the TD Bank Garden has been canceled.
BRUINS GAME CANCELED: Tonight's game against the Ottawa Senators has been canceled and has not been rescheduled.— Boston.com News (@BostonDotCom) April 15, 2013
5:04 p.m. Google sets up "Person Finder" for people seeking loved ones in the aftermath of explosions.
4:56 p.m. The FAA has announced ground stops for Boston Logan Airport.
BREAKING: FAA has announced a ground stop for Boston Logan airport until further notice— NBC Nightly News (@nbcnightlynews) April 15, 2013
#BostonMarathon presser: Police ask citizens 1-800-494-TIPS for information/tips, say they had no information this was going to happen— UPI.com (@UPI) April 15, 2013
4:54 p.m. Davis said many of the runners and spectators fleeing the scene dropped their bags, and officials are checking each one for explosives, but so far no other devices have been found.
The third explosion on Boylston Street was a controlled detonation, but was not an explosive device.
4:51 p.m. Press Conference.
Ed Davis, Boston Police Commissioner: Two simultaneous explosions, 50 to 100 yards apart. All victims have been removed from the scene.
"We immediately activated a system of response... in place for these types of incidents," Davis said.
An explosion at the JFK Library is being treated as related.
4:49 p.m. If anyone who was at the finish line took video, please send to the Boston Police Department.
4:48 p.m. Injury toll rises to 2 dead, 64 wounded.
MARATHON EXPLOSION: Toll rises to 2 dead, 64 wounded in Boston Marathon explosions.— Boston.com News (@BostonDotCom) April 15, 2013
4:45 p.m. More from a White House official:
"Shortly after being notified of the incident around 3pm EDT, the President received a briefing from Homeland Security adviser Lisa Monaco and other members of his senior White House staff in the Oval Office. The President called Boston Mayor Tom Menino and Massachusetts Governor Deval Patrick to express his concern for those who were injured and to make clear that his administration is ready to provide needed support as they respond to the incident.”
4:43 p.m. Boston Marathon Facebook update.
The Family Meeting Area has been moved to Boston Common. Runners are being directed there to meet friends and family. City of Boston assets have been deployed to assist runners at the Common.
4:30 p.m. CBS News: Massachusetts General Hospital physician said 19 wounded, 6 critical have been brought to that hospital.
BREAKING NEWS: Police getting multiple reports of unexploded devices around Boston— Boston.com News (@BostonDotCom) April 15, 2013
4:22 p.m. CBS: At least one more device, possibly two, discovered, destroyed by police.
We are currently in contact with Federal, State and City Officials.— Deval Patrick (@MassGovernor) April 15, 2013
4:19 p.m Arial footage of the finish line:
4:18 p.m. A BPD News conference is expected at 4:30.
4:16 p.m. Key areas along East Coast, including White House, Pentagon and key locations in New York City have stepped up security.
NYPD is stepping up security at hotels and prominent locations in NYC until more is known about #BostonMarathon.— NYC Mayor's Office (@NYCMayorsOffice) April 15, 2013
4:11: p.m. Boston Marathon officials released a statement on Facebook:
There were two bombs that exploded near the finish line in today’s Boston Marathon. We are working with law enforcement to understand what exactly has happened.
4:11 p.m. CBS News: Federal agents arriving on the scene to investigate.
4:05 p.m. Boston Police Department: 2 confirmed dead, 22 injured.
4:02 p.m. CNN reports: At least 19 people have been injured.
4:01 p.m. CBS confirms police detonated the third device.
3:58 p.m. White House press pool, from an official: The President has been notified of the incident in Boston. His administration is in contact with state and local authorities. He directed his administration to provide whatever assistance is necessary in the investigation and response.
3:57 p.m. Fox News: Additional unexploded devices have been located.
3:50 p.m. The 26th mile marker -- the last before the finish line -- had been designed to honor the victims of the Dec. 14 shooting at Sandy Hook Elementary in Newtown, Conn.
3:44 p.m. Video of one of the explosions at the finish.
3:38 p.m. CBS witness, a marathon runner, said he saw "well over a hundred people" going into the medical tent after the explosions.
3:31 p.m. WBZ: Several children among the injured. No indication yet on the cause of the explosions, or whether the explosions were set intentionally.
I saw people's legs blown off. Horrific. Two explosions. Runners were coming in and saw unspeakable horror.— Jackie Bruno (@JackieBrunoNECN) April 15, 2013
If you know anyone who was running in the marathon, you can check their status on the Boston Marathon Website, here.
3:28 p.m. CBS reports local hospitals have gone on emergency alert, expecting several casualties.
3:25 p.m. CNN reports a possible suspicious device at the Mandarin Hotel on Boylston Street, near Copley Square.