Witnesses report the explosions were about a mile away from the finish line.
At this time no new information about what was the cause of these explosions have been reported.
TWEET: (3:34p) CBS News reporting BOSTON area hospitals on ‘disaster alert’ to care for injured runners, and spectators..Witnesses report 2 explosions….
CNN Breaking News reports 4 people in Boston General in Critical Condition .
(4:19 p) According to hospital officials, at least 28 people are being treated for injuries connected to this afternoon’s blasts near the Boston Marathon finish line.
(4:30p) A video of the second blast in Boston on YouTube showing the reaction of witnesses.
[Update, 4:58 p.m. ET] New details from Boston Police Commissioner Ed Davis:
– A third explosion happened at the John F. Kennedy Presidential Library “about a half-hour ago.” The library is about 5 miles southeast of the Boston Marathon finish line.
– Police don’t immediately know whether that explosion is related to the two near the Boston Marathon finish line.
– The two blasts near the finish line – along Boylston Street near Copley Square – “happened 50 to 100 yards apart.”
– “We’re recommending to people that they stay home … and that they don’r go anyplace and congregate in large crowds.”
– Relatives of people who may be missing in the area can call the mayor’s hotline at 617-635-4500.
– Anyone who has information about the bombings or saw anything suspicious can call 1-800-494-TIPS.
[Update, 4:46 p.m. ET] Massachusetts Gov. Deval Patrick says “this is a horrific day in Boston.”
“My thoughts and prayers are with those who have been injured,” Patrick said in a statement released this afternoon. “I have been in touch with the president, Mayor Menino and our public safety leaders. Our focus is on making sure that the area around Copley Square is safe and secured. I am asking everyone to stay away from Copley Square and let the first responders do their jobs.”
[Update, 4:45 p.m. ET] It appears that so many people are using cell phones in the center of Boston, consistent service is hard to get – and the overload is hampering the investigation, two federal law enforcement sources tell CNN.
[Update, 5:15 p.m. ET] The Boston Globe is reporting a much higher injury count. They report that more than 100 people are being treated for injuries, citing local hospitals.
[Update, 5:10 p.m. ET] Hospitals now say they are treating as many as 51 wounded after the bombings. Two people have been killed, according to Boston police.
Cell phone service shut down in downtown #Boston to prevent detonation of devices, according to WBZ. on.cnn.com/139ikHp
[Update, 5:21 p.m. ET] Precautions are being taken at the White House because of the Boston explosions, CNN’s Jessica Yellin reports.
Boston police now appear to be backing away from their commissioner’s earlier statement that a third incident – at the JFK Library 5 miles from the finish line – might have been related to the Boston Marathon blasts.
On Twitter, Boston police say: “Update JFK incident appears to be fire related.”
[Update, 5:35 p.m. ET] Google has established a person-finder related to the Boston bombings. People who are looking for someone or have information about someone can make reports there.
[Update, 5:59 p.m. ET] John Manis, an eyewitness in his 50s, was about 200 feet away from the finish line near the Prudential building when the bombings occurred. He felt the blast to the point that it made him and others around him jump in the air, and some others around him fell down on the ground, he said, according to CNN’s Eden Pontz.
Manis said he heard two blasts about five seconds apart. He said there was confusion all around him, and he was hustled into the nearby Mandarin Hotel. Officials wouldn’t let them leave the hotel for a bit, and he says all who were there were all frisked by police. He said that when he left, he saw broken storefronts and lots of blood.
[Update, 6:14 p.m. ET] More from President Obama, who just wrapped up his brief statement at the White House: “We still do not know who did this or why … but make no mistake: We will get to the bottom of (this). We will find out who did this. We will find out why they did this. … Any responsible groups will feel the full weight of justice.”
[Update, 6:11 p.m. ET] President Barack Obama is speaking about the bombings now: “The American people will say a prayer for Boston tonight, and Michelle and I send out deepest thoughts and prayers to the victims,” Obama said at the White House.