Two explosions at the finish line of the Boston Marathon killed three people and injured more than 130 others while shattering the festive nature of the race and reigniting national fears about terrorism.

President Obama promptly characterized the incident as a terrorist attack, making official what many citizens had already concluded. The attack created pandemonium in the streets of Boston and a keen sense of unrest elsewhere.

"The American people will say a prayer for Boston tonight," Obama said. "And Michelle and I send our deepest thoughts and prayers to the families of the victims in the wake of this senseless loss."

About an hour after the Copley Square explosions, there were reports of another explosion at the JFK Library in Boston. The Boston police commissioner says that the incident at the library, which was a fire, seems to be unrelated to the Boston Marathon explosion.

For many in Boston, and throughout the country, the incident drew immediate parallels to the attack on the World Trade Center in New York City nearly a dozen years earlier. More than anything, it reinforced the feeling that terrorism remains part of the national landscape.

“Everyone here is feeling extremely uneasy because situations like this don’t happen in Boston,” said Lawrence Rock, a medical device salesman who lives in Boston, in an interview with BET.com.

The marathon, one of the largest and most prestigious events for runners in the United States, drew more than 23,000 participants. Roughly 17,000 had completed the race at the time of the bombings. The remaining runners were diverted or stopped.

Jason Marshall, a salesman for a health care company in Boston, was one such runner in the marathon. He was stopped at the 20-mile mark and told by officials of the explosions and that the race was cancelled.

“I immediately got calls from family members and friends who were concerned about me,” Marshall told BET.com. “But I got concerned because I had family members — my parents, my sister and my seven-month-old nephew — who were waiting for me at the finish line.”

In the end, he said, all his relatives were safe. But he and others he encountered were stunned and horrified.

“I am completely in shock,” Marshall said. “It’s wild. People seemed to be traumatized out there. I feel bad that I couldn’t complete the race I had trained for over the last five months. But there are people going through far more turmoil than that.”

Google and Red Cross have established an online person finder to help family members and friends find their loved ones. Cell phone service in Boston was overloaded after the attacks and some reports claimed that government officials had "shut down cell service to prevent more explosives from being detonated remotely," CNN reports. Sprint and Verizon Wireless disputed those claims.

Abdul Hafiz, a student at Northeastern University in Boston, said that the explosion had created “an extremely trying time for students here.”

Hafiz, a junior from Staten Island, New York, majoring in political science and international affairs, said: “Students here are shocked and stunned. It reminds us that we still have a level of terrorism that is still plaguing our communities. This is a reminder that the threat of terrorism is not going away any time soon.”

Officials ask that if you have information about the bombings, please call 1-800-494-TIPS.

BET's thoughts are with those affected by the bombing tragedy in Boston. Relatives of missing persons in Boston can call the Mayor’s Hotline at 617-635-4500.

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(Photo: David L. Ryan/The Boston Globe via Getty Images)