Terror act: 3 killed, more than 130 injured at Boston Marathon (video)

At least three people, including an eight-year-old, have been killed and more than a hundred injured after two explosions hit the finish line of the Boston Marathon. With other explosives found at the scene, it's being called a terror attack.

Eyewitnesses say smoke filled the streets of the city after a first explosion, and seconds later another loud boom was heard. The event has been put on hold and paramedics are quickly trying to assess the situation.

Earlier in the afternoon, 23-year-old Ethiopian runner Lelisa Desisa came in first-place by completing the run in 2 hours, 10 minutes and 22 seconds. At the time of the explosions, though, hundreds of runners were still racing for the finish line, AFP reports.

Organizers call the event the "world's oldest annual marathon and one of the world's most prestigious road races."

Law enforcement officials speaking to Fox News say that three victims have been reportedly killed in the explosions, although the Boston Police Department has yet to confirm this allegation. Another source at Boston's Mass General hospital tells the network that at least 10 patients have been admitted to the facility's emergency room with missing limbs after the accident.

The Boston Marathon’s headquarters have reportedly put on locked down while authorities investigate the incident. Preliminary reports suggest two explosions occurred near the finish line of the 26.2-mile event shortly before 3 pm local time, and the Boston Globe is reporting “at least dozens of people” suffering injuries at the scene.