First Reactions from the Finish Line at the Boston Marathon

Families were having fun at a party at the Mandarin Oriental Hotel, near the finish line of the Boston Marathon, enjoying the VIP view and watching kids run around. Then the bombs went off.

"The bomb went off directly in front of us," one parent, whose kids were watching at the window at the time, said on Facebook. "It is absolutely positively terrible. We are fine, but this is an ultimate tragedy."

Also on Shine: Boston Marathon Explosions: How You Can Help and Stay Informed

Two explosions at 2:50 p.m. near the finish line of the Boston Marathon left at least two dead (including an 8-year-old child) and more than 100 people injured along Boylston Street in Boston on Monday, shattering windows and leading police to shut down much of the Copley Square area. Finish line volunteers were told to run, and later told reporters that their fear felt "like 9/11 or the tsunami." Many of the people taken to local hospitals ended up losing limbs. Some runners used their lanyards as tourniquets.

"We started grabbing tourniquets and started tying legs," a Rhode Island state trooper, who had just finished running the race, told WCVB News. He immediately started helping victims."At least 25 to 30 people have at least one leg missing, or an ankle missing, or two legs missing." A doctor at nearby Massachusetts General Hospital said that the area looked like "a war zone."

"When I looked up, I saw people with bloody heads, people with their shirts blown off," one spectator told The Boston Globe's Michael Levenson. Another witness told him, "I'm just going to sit here and cry."

The blast was so strong that some people said they could feel the heat on their faces, and the impact was felt several blocks away.

"I was turning the corner. I was near the Hynes Convention Center," one runner told WCVB. "I saw two explosions. I just turned around and ran. It was a fireball—a huge fireball." Journalists on the scene spoke of smelling gunpowder, blood, and burning hair, and seeing sidewalks splashed with blood.

Senator Dianne Feinstein, chairman of Intelligence Committee, told ABC News "It is a terrorist incident," and President Barack Obama offered his condolences and promised justice.

"All Americans stand with the people of Boston," the President said in a televised statement. "We still do not know who did this or why. Make no mistake—we will get to the bottom of this. We will find out who did this. We will find out why they did this."

The attack affected Boston residents on another level as well. Monday was Patriots' Day, Massachusetts' unofficial celebration of springtime and freedom, marking the first battles of the American Revolutionary War.

"For those who've never lived in Boston, it's hard to explain what a great day Patriot's Day is," Julie Roginksy, who graduated from Boston University, told her friends on Facebook. "It means the advent of spring and the marathon, which is the most communal event I've ever witnessed in any city. What a tragedy that it will also mean something else going forward."

The last mile of the marathon had been dedicated to the children who died in the Sandy Hook Elementary School shootings in Newtown, Connecticut, and some of their parents were seated in the stands. Instead of an uplifting memorial, they were forced to witness another violent tragedy; at least one undetonated device was found under the stands. Officials said that they do not know if any of the Sandy Hook parents were among the victims of the blasts on Monday.

"I only have a shred of understanding of what it would be like to be traumatized twice like this," Tweeted Michael Ditto. "I'm sobbing for the Newtown families."

More than three hours after the explosions, "The sirens haven't stopped," Tweeted Patrick D. Rosso. Though people have been encouraged to donate blood, Governor Deval Patrick asked that non-essential personnel stay away from local hospitals while doctors and nurses work to triage victims. Other unexploded devices were found near the scene, and were being dismantled. An electrical fire at the John F. Kennedy Museum and Library—five miles away—was at first thought to be another bomb, but later determined to be unrelated.

"People running for charity, seeking to help others out of compassion & humanity are terror targets? It defies belief," Tweeted Des Kelly

In the hours after the explosion, hundreds of people milled around streets a few blocks away from the finish line, trying to locate friends and family members. "Confusion and rumor are everywhere. No one seems to know what do to," Boston Globe reporter Billy Baker tweeted. "Lots of hugging and crying." Marathon runners who were still on the course were not allowed to finish the race; instead, they were redirected to other areas of the city. By late afternoon, transportation services in parts of the city had shut down, leaving some runners stranded far from home. Boston residents were asked to open their homes to stranded athletes, and bars along club-heavy Lansdowne street, near the Fenway area, were packed.

"This is a horrific day in Boston. My thoughts and prayers are with those who have been injured," Governor Patrick said in a statement. "I have been in touch with the President, Mayor Menino and our public safety leaders. Our focus is on making sure that the area around Copley Square is safe and secured. I am asking everyone to stay away from Copley Square and let the first responders do their jobs."

With cell phone service unreliable, many people flocked to Facebook to check in on loved ones and get updates on the explosions. The Boston Marathon's Facebook page was flooded with condolences, prayers, and support from runners around the world.

"Prayers offered from Dublin in Ireland for everyone affected by this," wrote Carmel Ward.

"God bless all of you in Boston," wrote Rocco Lucchi. "Thoughts and prayers from Forli, Italy."

Others offered thanks to those who stepped forward to help.

"Absolutely horrific and such a waste of life. My thoughts and prayers go to the families and friends of all those killed and injured," wrote Christine Gilbert. "My thanks go to all those assisting and supporting those involved in this tragedy."