Two explosions have been reported in Boston, Massachusetts where thousands of runners are participating in the annual Boston Marathon.

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.

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.

The Boston Marathon’s headquarters have reportedly put on locked down while authorities investigate the incident.

Eyewitnesses say smoke filled the streets of the city after a first explosion, and seconds later another loud boom was heard.

“I saw two explosions. The first one was beyond the finish line. I heard a loud bang and I saw smoke rising,” Boston Herald reporter Chris Cassidy says from the scene. “I kept running and I heard behind me a loud bang. It looked like it was in a trash can or something.”

“There are people who have been hit with debris, people with bloody foreheads,” he says.

Witness Andrea Storer adds to the Globe, “It was huge. There had to be people killed. There had to be.”

"Blood everywhere,” another witness tells the paper.

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.

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

RT