16:09

Police still guarding the front entrance of Brigham and Women's Hospital in Boston, reports Jim Lokay of WCVB. He continues: At last check, 31 of the injured are being treated at the hospital.

15:53

France has ordered police patrols and security around public buildings to be stepped up, The Wall Street Journal reports. "New precautionary measures were taken without panic and dramatization," Interior Minister Manuel Valls said Tuesday on RTL radio.

French police were already at a heightened state of awareness following the country's military intervention in Mali to dislodge Islamist militants there, Mr Valls added.

The police earlier this year raised the national security alert to "strengthened red", the second-highest level.

15:26

Boston native actor Mark Wahlberg spoke of his own personal gain and pain from being in New York last night for the premiere of his new film 'Pain and Gain'.

"I really didn't even want to come tonight. I hadn't really heard much - I spoke to my mom, and most of my family seems to be OK. It's such a big event, there's so many people there. It's horrible man. It's (expletive) disgusting, man. I just - I'm very upset."

"You try to put everything in God's hands and whatever happens here is out of our control and there's a bigger picture. But it's still obviously upsetting."

15:00

The brothers who both went to watch the Boston Marathon and ended up each losing a leg are just some of the horror stories emerging from the city. Kevin Cullen also writes about “In an instant, a perfect day had morphed into something viscerally evil’ in one of a number of excellent stories from the Boston Globe. [Read More]

14:11

The Boston Fire Dept tweeted: A sad day but a day where training, pre-planning, unified command and a quick first response by many saved lives. Meanwhile, the hunt for the bombers continues as the FBI examines the crime scene and unexploded device.

14:05

Teams of federal and local law enforcement agents searched an apparently vacant fifth floor apartment on Ocean Avenue in the Boston neighborhood of Revere, residents told ABC News.

Marcus Worthington, a law student who lives in the apartment complex, said he saw dozens of law enforcement vehicles arrive at his building Monday afternoon, including FBI, ATF and local police and fire departments.

13:40

The first names of the victims are beginning to emerge. The Boston Globe has named the 8-year-old killed as Martin Richard, the son of William and Denise Richard who are in hospital injured alongside their daughter. Another daughter waiting at the finish line in the race was unharmed. The family is reportedly from the Ashmont section of Dorchester where their father Bill is a community leader.

12:59

Sporting games across the US are being cancelled out of respect to the victims of the bombing, networks in the US report.

12:54

Retired FBI bomb technician Kevin G. Miles said the attack could "easily" have been the work of one person in an op-ed in the Boston Herald.

12:45

The US Secret Service is expanding the security perimeter surrounding the White House following the tragic events in Boston, Fox News reports.

11:39

The FBI, who is now leading the investigation, will hold a news conference on Tuesday, April 16 at 9:30 pm (Beijing time) at The Westin Copley Plaza in Boston. Meanwhile, Arlington Street Church will hold candlelight vigil.

11:31

WBZ-TV is reporting that just about every federal agency (FBI, ATF, DHS) and bomb squad is serving a search warrant in Revere near Boston.

11:24

Jim Assiante, who was a first-responder at the scene working in triage, is telling CNN "There was lots of smoke, confusion, blood, lots of screaming, injured patients. For me it was a flashback to Iraq. We did what we had to do with the best of what we had."

Stephen Segatore, another triage worker, added he treated children, mothers, elderly who had horrific injuries and "we did the best we can, work aggressively to save them".

11:10

Despite the blast, two runners went on to marry just hours after the explosion

10:45

Boston Globe photographer John Tlumacki, who was shooting pictures at the finish line when the explosions went off has given an interview to Time Magazine. His images can only be described as horrific and will dominate tomorrow's US front pages. http://lightbox.time.com/2013/04/15/tragedy-in-boston-one-photographers-eyewitness-account/#1

He said:"The first thing I saw were people's limbs blown off. Massive amounts of blood. It looked like BB holes in the back of some people. And a lot of anger. People were just angry. What's going on? Why is this happening at the Boston Marathon?"

"Maybe 15 seconds after the first explosion, while I was still shooting pictures, another explosion went off. And then there was panic. The cops told everybody to get off the street, that there could be another one."

10:31

A police BOLO - Be On the Look Out notice – has been issued for a 'dark-skinned, black man' who was trying to enter the marathon site just before the blast, according to CNN. Police have also said a report of a Saudi national wounded in the leg in hospital is not a suspect.

10:26

Boston Police Department tweets; Commissioner Davis: “The BPD is on high alert. All sworn personnel working around the clock. 12 hour shifts in effect. Days off cancelled.

10:25

UN Secretary-General Ban Ki-moon said the bombing "is all the more appalling for taking place at an event renowned for bringing people together from around the world in a spirit of sportsmanship and harmony.

10:23

140 patients treated at 8 Boston hospitals for injuries from bomb blast, according to Boston Globe.

10:17

Massachusetts General surgeon speaking on CNN says received 29 patients, 8 in critical condition

09:45

Police in UK to review security arrangements for Sunday’s London marathon where 37,500 people compete, Reuters reports.

09:38

Boston blasts show two sides of social media. Twitter spread news of the blasts quickly and was a useful communications tool for public authorities. There was also misinformation. Link: http://www.pcworld.com/article/2034702/boston-blasts-show-two-sides-of-social-media.html

09:30

Casualty count in Boston marathon terror attack - 3 killed, 141 injured. 17 in critical, 25 in serious condition, according to CNN.

09:17

Marathon runner Bil Iffrig, 78, who was pictured on the finish line being knocked down by the force of the blast tells CNN, “I felt a tremendous shockwave hit my body and fell down. I didn’t feel any pain, but the force was so strong.” His image and video is being broadcast around the world.

09:08

Boston Police Commissioner Ed Davis says no further devices have been found but there are reports of suspicious packages. The news conference has now ended.

09:00

Police Commissioner Edward Davis ruled out earlier reports they were holding a suspect and confirmed the death toll has risen to 3.

08:57

US Attorney’s Office tells press this is a horrific tragedy and we will provide all the resources necessary to this “fluid” investigation.

08:52

The FBI and Boston police are holding a joint news conference on the investigation into the marathon explosions. Massachusetts Governor Deval Patrick says The National Guard has secured the crime scene around the bomb site and a support center has been opened for victims. He says police will not confirm details of injuries or deaths.

08:47

Wall Street Journal reports officials have found what they believe are five additional, undetonated explosive devices in Boston area.

08:42

Boston police will give new updates on the incident in a news conference in the next 10 minutes. We will bring you updates here on China Daily's live report.

08:24

One child is reportedly among the dead, several news outlets in the US report.

08:22

Massachusetts Governor Deval Patrick says a no-fly zone has been put in place around the site but it will not affect commercial flights at Boston's Logan Airport, CNN reports.

08:20

Reports from the hospitals where victims are being treated claim people have suffered horrific injuries with amputations and ball bearings people pulled from open wounds, BBC reports.

08:00

The Boston Police Commissioner is giving a news conference appealing to people to stay away from bomb site and families of victims to get in touch, he says the situation is "on going".

06:17