Police radio recordings from the moments after the terror attack on the Boston Marathon have revealed the chaos officers suddenly found themselves working in.
Officers in multiple locations are heard calling in to the operator desperately pleading for ambulances while at the same time searching for additional explosive devices.
'Send as many ambulances as you can,' one police supervisor shouts.
Scroll down to hear scanner traffic
Response: Boston police officers drew their guns as they heard the second blast further down the street - meanwhile 78-year-old Bill Iffrig lay dazed on the floor
Explosion: Pictures show runners approaching the finish line in Boston as the bomb erupts on the sidewalk
Later in the recording the operator warns of the dangers telling officers: 'There are other possible devices in the area'.
Officers are heard shouting at the operator while others try - as calmly as possible - to bring order to the situation.
It reveals the stresses the Boston Police Department faced when it was thrust from handling a gentle spectator event to a major terrorist attack in the blink of an eye.
The operator struggles to hear over the background noise and repeatedly warns officers against calling in all at once.
He repeatedly reassures them that ambulances are on the way.
Police radio transcript
Unidentified officer: 'Send as many ambulances as you've got.'
Unidentified officer: 'There's definitely another device! I need officers! There's definitely another device!'
Officer Delta 984: 'I need ambulances'.
Operator: 'Units stay off the air, units stay off the air and just make your way over there. Units stay off the air and make your way over there I only want to hear from Delta 984
Officer Delta 984: Here's what I need. I need the ring road cleared so I can let ambulances out, okay? I need as many ambulances as you can give me. I want ring road cleared to let ambulances in and out. I need lanes open here
Operator: Copy. Just keeping giving it out, Sir. Anyone else stay off the air.
Various officers call in with police codes and locations around the city
Officer Delta 984: ' I need people up from the medical tent. Get as many people up here as you can from the medical tent. We're going to need more ambulances.'
Operator: 'They're going Sir, they're going'
Unidentified officer: 'I have multiple people down here, I don't know what the cause is'
Unidentified officer: Get vehicles off the road we're going to need ambulances in here
Officer Delta 984: Transfer all the units from the city to this team now please
Operator: 'Use caution there are other possible devices in the area'
Audio: Listen to police radio traffic
LISTEN: Boston Marathon bombing horror unfolds on Police scanner
'I need lanes open here', one officer shouts. 'Get as many people up here from the medical tent. I'm going to need more ambulances.'
The police supervisor said ambulances could not get through the crowded traffic or roads that were blocked off because of the marathon.
Empty ambulances couldn't get in and ambulances with patients could not get out.
'I need as many units as you can give me,' he told the dispatcher.
Later, he repeats: 'We're going to need more ambulances here.'
He then asks the dispatcher to call the personnel from the medical tent up to the site of the bomb blasts to help stabilize the wounded.
All off-duty police officers were called back in to work in Boston yesterday.
Police Commissioner Ed Davis told the department last night: 'The Boston Police Department is on high alert. All sworn personnel working around the clock. 12 hour shifts in effect. Days off cancelled.'
Rescue mission: Emergency personnel tend to the wounded after two explosions went off near the race's finish line yesterday
On-duty: Emergency responders comfort a woman on a stretcher who was injured in the explosions yesterday
Officers in multiple locations are heard calling in to the operator desperately pleading for ambulances while at the same time searching for additional explosive devices.
'Send as many ambulances as you can,' one police supervisor shouts.
Scroll down to hear scanner traffic
Response: Boston police officers drew their guns as they heard the second blast further down the street - meanwhile 78-year-old Bill Iffrig lay dazed on the floor
Explosion: Pictures show runners approaching the finish line in Boston as the bomb erupts on the sidewalk
Later in the recording the operator warns of the dangers telling officers: 'There are other possible devices in the area'.
Officers are heard shouting at the operator while others try - as calmly as possible - to bring order to the situation.
It reveals the stresses the Boston Police Department faced when it was thrust from handling a gentle spectator event to a major terrorist attack in the blink of an eye.
The operator struggles to hear over the background noise and repeatedly warns officers against calling in all at once.
He repeatedly reassures them that ambulances are on the way.
Police radio transcript
Unidentified officer: 'Send as many ambulances as you've got.'
Unidentified officer: 'There's definitely another device! I need officers! There's definitely another device!'
Officer Delta 984: 'I need ambulances'.
Operator: 'Units stay off the air, units stay off the air and just make your way over there. Units stay off the air and make your way over there I only want to hear from Delta 984
Officer Delta 984: Here's what I need. I need the ring road cleared so I can let ambulances out, okay? I need as many ambulances as you can give me. I want ring road cleared to let ambulances in and out. I need lanes open here
Operator: Copy. Just keeping giving it out, Sir. Anyone else stay off the air.
Various officers call in with police codes and locations around the city
Officer Delta 984: ' I need people up from the medical tent. Get as many people up here as you can from the medical tent. We're going to need more ambulances.'
Operator: 'They're going Sir, they're going'
Unidentified officer: 'I have multiple people down here, I don't know what the cause is'
Unidentified officer: Get vehicles off the road we're going to need ambulances in here
Officer Delta 984: Transfer all the units from the city to this team now please
Operator: 'Use caution there are other possible devices in the area'
Audio: Listen to police radio traffic
LISTEN: Boston Marathon bombing horror unfolds on Police scanner
'I need lanes open here', one officer shouts. 'Get as many people up here from the medical tent. I'm going to need more ambulances.'
The police supervisor said ambulances could not get through the crowded traffic or roads that were blocked off because of the marathon.
Empty ambulances couldn't get in and ambulances with patients could not get out.
'I need as many units as you can give me,' he told the dispatcher.
Later, he repeats: 'We're going to need more ambulances here.'
He then asks the dispatcher to call the personnel from the medical tent up to the site of the bomb blasts to help stabilize the wounded.
All off-duty police officers were called back in to work in Boston yesterday.
Police Commissioner Ed Davis told the department last night: 'The Boston Police Department is on high alert. All sworn personnel working around the clock. 12 hour shifts in effect. Days off cancelled.'
Rescue mission: Emergency personnel tend to the wounded after two explosions went off near the race's finish line yesterday
On-duty: Emergency responders comfort a woman on a stretcher who was injured in the explosions yesterday