Minute-by-minute updates on the Boston explosions

9:54 p.m.: Monday's twin blasts took place about 10 seconds and 100 yards apart, knocking people off their feet and shattering nearby windows, The Associated Press reports.

9:10 p.m.: The Boston Athletic Association releases a lengthy statement regarding the tragic events. It reads, in part: "Today is a sad day for the City of Boston, for the running community, and for all those who were here to enjoy the 117th running of the Boston Marathon. What was intended to be a day of joy and celebration quickly became a day in which running a marathon was of little importance."

8:58 p.m.: A third person has died from injuries sustained in the explosions, Boston police say. And that number could climb.

8:50 p.m.: The FBI says it is assisting law enforcement in Boston with the investigation into the explosions. The FBI has set-up 1-800-CALL-FBI (1-800-225-5324), prompt #3, for anyone who has information, visual images, and/or details regarding the explosions along the Boston Marathon route and elsewhere. No piece of information or detail is too small, the FBI said.

8:05 p.m.: Boston police are asking anyone with information for the investigation to call the BPD's Crime Stoppers Tip Line at 1-800-494-TIPS. Callers can remain anonymous.

7 p.m.: MARTA says it is taking proactive security measures and releases a statement: "In response to the explosions in Boston, MARTA is exercising an abundance of caution and heightening security on the transit system. While at this time there are no credible threats to transit, MARTA is asking employees and customers to be vigilant and remain on high alert.

The MARTA Police Department (MPD) is working directly with federal, state and local agencies, including the Massachusetts Bay Transit Authority (MBTA) and the Transit Security Administration (TSA) in Washington, D. C. to stay updated on any recommendations related to public transit.”

6:44 p.m.: Atlanta Mayor Kasim Reed releases the following statement regarding the events: "My thoughts and prayers are with the City of Boston today and all those who have been affected by today's tragic events. I am deeply saddened to hear of the loss of life and injuries suffered by so many people. Here at home, the City of Atlanta's First Responders are currently taking additional measures to enhance the safety of our citizens and protect them from senseless acts of violence."

6:42 p.m.: An 8-year-old is reportedly one of the two killed in the explosions, NBC News reports.

6:30 p.m.: The Atlanta Braves organization releases the following statement: "Our awareness is heightened. We have been and remain in communication with law enforcement, public safety and other appropriate agencies as we prepare for our games tomorrow and Wednesday. Our thoughts and prayers go out to all of those affected by this tragedy."

6:21 p.m.: Runner Christy Duffner tells Channel 2 Action News people are crying in her hotel, which remains on lockdown. She was not injured, but heard the explosions.

6:09 p.m.: "We still do not know who did this or why," President Barack Obama says. "We will find out who did this and we will hold them accountable."

5:51 p.m.: Area where explosions occurred to be closed for the "foreseeable future," Boston police says via Twitter.

5:47 p.m.: President Barack Obama is expected to address the nation at 6:10 p.m.

5:42 p.m.: Online Google link can help you find friends and family affected by the explosions in Boston.

5:40 p.m.: Death toll still at two, but number of injured climbs to more than 50.

5:27 p.m.: No one has claimed responsibility for the two deadly explosions, The Associated Press reports.

5:23 p.m.: Atlanta Track Club Executive Director Tracey Russell released the following statement: "We are deeply saddened to hear the news of today's events in Boston. Safety at every Atlanta Track Club event is our top priority. As it relates to security with any large-scale event in Atlanta, we work very closely with the City's Police and Fire Departments and Emergency Medical Service units, as well as the Federal Emergency Management Agency and additional government agencies. Our hearts go out to the entire Boston community and the victims affected by this tragedy."

5:18 p.m.: Here is the hotline for family members looking for information on Boston Marathon victims: 617-635-4500.

5:13 p.m.: Tuesday at 7 a.m., a moment of silence and run will be held at the Big Peach Running Co. in Midtown in honor of those killed and injured.

5:05 p.m.: Cell phone service shut down in Boston to prevent any remote detonations for additional explosions.

5:01 p.m.: More reactions from Georgia runners in Boston.

4:54 p.m.: Boston police commissioner urges people to stay indoors, not congregate in large groups.

4:50 p.m.: FAA orders no-fly zone over Boston explosion site.

4:30 p.m.: View the scene in Boston.

4:25 p.m.: Georgia's top finisher, Malcolm Campbell, crossed the finish line at 12:23 p.m. as the 36th finisher. Campbell, 42, of Marietta, said he mingled with other runners for an hour or so before heading back to his hotel a few blocks away. He didn't hear the explosions, but is trying to reach other friends and fellow runners. "It's not good," Campbell told The AJC. "If this was a terrorist event, the sport's landscape is going to change."

4:17 p.m.: Gwinnett County Commissioner Mike Beaudreau was among the runners. He texted home to notify his family he is OK. Read more.

4:08 p.m.: Boston Police Department confirms 2 dead, 23 injured in 2 explosions near marathon finish line, according to the Associated Press. Boston police will hold a press conference at 4:30.

4 p.m.: David Calhoun, from Dallas, Ga. tells Channel 2 Action News phone lines are jammed, but text messages are going through. Transportation in and out of Boston is shut down.

3:45 p.m.: Marietta native Michael Martin, who plays trumpet in the Boston Symphony Orchestra, posted the following on Facebook: "I'm in rehearsal at the hall, a few blocks from Copley Square/the finish line. Sirens everywhere. Praying all our friends are safe."