US President Obama promises full weight of justice to terrorists that attacked largest sports tourism Boston Marathon event

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U.S. President Obama spoke to the American People from the Oval Office less than three hours after two explosions at the Boston Marathon on Patriots Day, a holiday in Boston. President Obama did not call it a terrorist attack yet but promised those that did this would pay for it. After the presidents briefing Homeland Security now speaks about a coordinated event.
According to an unconfirmed eTN source a Saudi Arabian citizen may have been arrested. Click here for more information.

After the first 2 deadly exposition, a third explosion was just confirmed at the JFK Library around 4.20pm Boston time. It later turned out this was an accident and unrelated to the terrorist attack.
Authorities in New York, Washington and Los Angeles were put on alert.
Federal authorities took over the lead of the investigation.

The United States Tour Operator Association (USTOA) tweets: Our thoughts go out to people at the Boston Marathon and hope you are well and safe.

The Boston Marathon is one of the largest tourism events in Boston. 27,000+ Participants from 56 countries includes Ethiopian Lelisa Desisa who won in a sprint of runners.

Shortly after this news, a pair of explosions resulted in a lock down after an explosion was reported near the finish line in the center of town. The streets of Boston were very busy with spectators and tourists on this New England holiday. The Boston Police confirmed several people including an 8 year old child died. The Boston Globe reports hundreds of injuries, some critical.

Counter terrorist experts found at least 2 more explosives according to Associated Press.

Bloody spectators were being carried Monday afternoon to the medical tent that had been set up to care for fatigued runners. Police wove through competitors as they ran back toward the course.

Reports are looking at explosives found at the Mandarin Hotel.

“There are a lot of people down,” said one man, whose bib no. 17528 identified him as Frank Deruyter of North Carolina. He was not injured, but marathon workers were carrying one woman, who did not appear to be a runner, to the medical area as blood gushed from her leg. A Boston police officer was wheeled from the course with a leg injury that was bleeding.

About 3 hours after the winners crossed the line, there was a loud explosion on the north side of Boylston Street, just before the photo bridge that marks the finish line. Another explosion could be heard a few seconds later.

Earlier President Barack Obama called Boston Mayor Tom Menino and Massachusetts Governor Deval Patrick on Monday to offer U.S. assistance in responding to the explosions that rocked the end of the Boston Marathon.

A White House official said Obama was notified of the incident around 3 p.m. EDT (1900 GMT) and was briefed by Homeland Security adviser Lisa Monaco and other members of his senior White House staff in the Oval Office.