A 'huge explosion' heard across Liverpool reportedly woke people from their beds and shook their homes.
Residents in the South Liverpool and Aigburth areas took to Twitter at around 11pm to discuss the loud bangs they had heard.
It is believed that people living here heard one "loud bang" before a series of smaller noises were also heard, followed by the sound of police sirens .
People said that the noises made their back doors shudder and windows vibrate as others tried to determine the cause of the startling noises.
Twitter user Tony Cowin said: "Anybody hear a huge explosion in South Liverpool/ Aigburth area just now? Police sirens straight after?"
Mo Alex Austin also said: "Jeez massif bang in Aigburth just now shook the whole house! Any ideas anyone?"
Charlotte Corbett added that the loud bang could also be heard near Festival Gardens.
She said: "I'm by festival gardens in #liverpool and just heard what sounded like an explosion and then a police car."
The ECHO attempted to contact the emergency services to confirm what caused the explosion noise but it is not clear where it has come from.
A number of people on Twitter believe that the bangs could have come from training exercises that have been taking place at a nearby abandoned halls of residence.
Ad Brown tweeted a link to an article reported previously and said: "Hopefully this. Thought it was a gas explosion."
He later tweeted: "Definitely coming from the halls, my road backs onto it.
"Been a couple of smaller bangs since, feared the worse tbh."
On Thursday afternoon, it was confirmed that emergency services were carrying out a number of training exercises at Carnatic Halls in Mossley Hill in order to test emergency services response in the event of a terrorist attack.
A witness reported seeing armed police in a car, men in white suits and a tarpaulin sheet over some of the site.
Pictures also showed an police matrix van and an ambulance outside the former student halls, which closed in the summer.
Officers from Merseyside Police and Counter Terrorism Policing North West, along with a number of partner agencies including local councils, Merseyside Fire and Rescue Service, North West Ambulance Service and Merseytravel all took part in the exercise.
A spokesperson for Merseyside Police said: "Training exercises like this are designed to test all those who would be involved in the joint response to such an incident to ensure we can provide an effective response to safely bring the incident to a close and keep our communities safe."
The force also said they sent letters to people living in the area to let them know the training was taking place.
