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.

12:47

First look at Tuesday's front page of the Boston Globe

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".

Members of the Calgary Flames' observe a moment of silence for those killed and injured in the Boston Marathon bombing today before the start of their NHL hockey game against the Minnesota Wild in Calgary, Alberta, April 15, 2013.[Photo/Agencies]

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.

09:30

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

Obama says mobilizing resources to probe into Boston explosions

Obama says to get to the bottom of Boston blasts, bring all responsible to justice

Obama says increase of security in US is necessary

05:47

WASHINGTON - Police said on Monday that a third explosion hit the Boston JFK Library, but it remains unclear whether it was related to the previous two blasts near the finish line of the Boston marathon.

"There was a third explosion at the JFK library," Boston Police Commissioner Ed Davis said at a press conference, adding that he was not yet aware of any injury in the third explosion.

Davis announced a police tipline for information that could lead to the arrest of those who were responsible for the attacks. He also advised people to stay at home or in the hotel.

Meanwhile, US media reports said that the number of those injured in the explosions has soared to over 100, with at least two deaths.

Map of the site. [Photo/Reuters]

03:27

WASHINGTON - At least two were dead, 28 injured in two explosions taking place near the Boston Marathon finish line on Monday afternoon, US media reported.

CNN still image taken from video shows the scene of an explosion at the 117th Boston Marathon in Boston, Massachusetts, US, April 15, 2013. [Photo/Xinhua]

President Barack Obama has been notified of the incident in Boston, a White House official told White House pool media.

Obama directed his administration to provide whatever assistance necessary in the investigation and response, said the official.

Intelligence officials said two more explosive devices have been found at Boston Marathon before being dismantled, media here reported.

The organizers of the Boston Marathon said on Facebook page that bombs caused the two explosions.

The Boston police bomb squad were sweeping the area for suspicious packages, ABC reported. Law enforcement authorities also told ABC they were testing smoke and materials at the scene for chemical substances.

The two explosions happened at around 3 pm and went off within seconds of each other. The first runners in the marathon crossed the finish line around noon.

The Boston Police Department said two explosions happened on the Boyleston street near the finish line. Local police, fire and bomb squad have arrived at the scene responding to the incident.

A man in a wheelchair is taken from the scene after explosions went off at the 117th Boston Marathon in Boston, Massachusetts April 15, 2013. [Photo / Xinhua]

A photographer with Fox affiliate WFXT reported a number of victims with lost limbs.

CNN's video showed heavy smoke on the street, while emergency crews were treating the injured. Bleeding spectators were seen being carried to the medical tent set up to care for the runners.

Many of the injured appeared to be spectators who had gathered at the scene, local media WCVB.com reported. The area has been evacuated.

Police in New York and Washington DC have also beefed up security around the cities in the wake of explosions.