Two explosions at the finish line of the Boston Marathon

Photo courtesy of ABC News

Three people died, including an 8-year-old child, and more than 144 people were injured Monday when two bombs exploded almost simultaneously about 100 yards apart at the finish line of the Boston Marathon. At least 17 of the injured are in critical condition.

A former Army medic says the scene was "more like Baghdad and Bombay than Boston."

Bruce Mendelsohn was attending a post-race party in an office building just above the blast site when an explosion knocked him to the floor. He rushed outside and found blood, glass and debris everywhere, and began applying pressure to what he calls "gruesome" wounds.

One of the runners describes a gruesome scene inside a medical tent near the finish line, as bombing victims were brought in "with no limbs." He says he tried to shield his children's eyes, but says "they saw a lot."

Roupen Bastajian, a Rhode Island state trooper, had just finished running the race when he heard the blasts. He says, "At least 25 to 30 people have at least one leg missing, or an ankle missing, or two legs missing."

The injuries range from cuts and bruises to amputations. Many victims suffered lower leg injuries and shrapnel wounds. The department of emergency medicine chief at Beth Israel Deaconess Medical Center says one or two of the hospital's 21 patients face a "high probability of mortality."

There's been no claim of responsibility for the twin bombings in Boston, and there's no word on a motive. But a White House official speaking on condition of anonymity because the investigation was still unfolding says the attack is being treated as an act of terrorism.

American Muslim organizations are condemning the Boston Marathon bombings and urging Americans of all faiths to join them in praying for the victims and their families.

The Council on American-Islamic Relations also is asking American Muslims to offer authorities any leads they may have to help capture the perpetrators of Monday's blasts.

CAIR spokesman Ibrahim Hooper says it's unfortunate that Muslims are often instantly considered suspects in such attacks.

The Muslim Public Affairs Council and the Muslim Peace Coalition USA also condemned the Boston bombings and extended condolences to victims and their families.

A senior U.S. intelligence official says two other bombs were found near the end of the 26.2-mile course in what appeared to be a well-coordinated attack. The two unexploded bombs were safely disarmed.

It was not immediately clear what kind of devices had been found Monday. The official said the first two did appear to be bombs.

The official spoke on condition of anonymity because he was not authorized to discuss the findings publicly.

A White House official says the attack is being treated as an act of terrorism. President Barack Obama says those responsible will "feel the full weight of justice."

WBZ-TV in Boston is reporting that that law enforcement officers are searching an apartment in the Boston suburb of Revere, following Monday's attack. Massachusetts State Police will only say that a search warrant related to the investigation has been served in Revere.

As the FBI takes charge of the investigation, authorities have shed no light on a motive or who may have carried out the bombings.

Police in Los Angeles, New York City, London and other cities worldwide are stepping up security following explosions at the Boston Marathon.

Los Angeles County Sheriff's spokesman Steve Whitmore says the department has opened an emergency operations center, increased patrols for transit and other critical areas including the Los Angeles Dodgers game Monday night

Chief NYPD spokesman Paul Browne said Monday that critical response teams are deployed around the city. Officials are stepping up security at hotels and other prominent locations.

British police also say they are reviewing security plans for Sunday's London Marathon. It's the next major international marathon. A London Metropolitan Police spokesman says police are working with marathon officials to review security plans

The White House says President Barack Obama has called Boston's mayor and the Massachusetts governor to express his concern for those injured in the Boston Marathon explosions.

Cellphone companies say service is operating in the Boston area, but with heavy traffic following of the explosions at the Boston Marathon.

A law enforcement official, citing an intelligence briefing, said cellphone service had been shut down Monday in the Boston area to prevent any potential remote detonations of explosives.

But officials with Verizon Wireless and Sprint Nextel said there had been no such requests.

Sprint spokeswoman Crystal Davis said: "Minus some mild call blocking on our Boston network due to increased traffic, our service is operating normally."

The only nuclear power plant in Massachusetts has increased security.

Local Runner Kelly Luckadoo, of Florence, said this via Facebook: "No phone or cell service here other than texring and FB which are both slow. I finished 30min prior to explosions, and we were on our way back to hotel 2 blocks away... It's so very sad and scary. Police want no one in this area (Back Bay) leaving their homes/hotels.It was a very special day where I ran my best time ever (PR 3:34) and qualified at Boston for my next Boston only to be clouded with such tragedy! I can't wait to get home, hopefully tomorrow."

Authorities went onto the course to carry away the injured. Those who hadn't yet finished the race were rerouted away from the area.

Smoke rose from the blasts, fluttering through the flags lining the route. TV helicopter footage showed blood staining the pavement in the popular shopping and tourist area known as the Back Bay.

Google is stepping in to help family and friends of Boston Marathon runners find their loved ones after explosions near the finish line.

The site, called Google Person Finder, allows users to enter the name of a person they're looking for or enter information about someone who is there.

According to the Boston Marathon website, at least 135 people from South Carolina were running today.

There are at least 13 runners from the Grand Strand and Pee Dee who ran in the Boston Marathon this year.

Here is a list of the local runners we are aware of:

Myrtle Beach - 5

Florence- 2

Pawleys Island - 1

Murrells Inlet - 1

Surfside Beach - 1

North Myrtle Beach - 1

Hartsville - 1

Marion - 1

The Grand Strand Running Club said all of its members who were running are accounted for.