A suspected Islamic extremist armed with an assault rifle, handgun and an explosive device has shot more than 40 people – killing around 20 – after taking party-goers hostage inside a nightclub in Orlando.

An unknown number of people were killed and 42 were taken to hospital after the gunman, believed to be in his 20s, opened fire inside Pulse nightclub.

Orlando Police Chief John Mina says authorities have not determined an exact number of people killed, but that ‘approximately 20’ have died.

An FBI spokesman says the mass shooting is being investigated as an act of terrorism. He says authorities are looking into whether this was an act of domestic or international terror, and if the shooter was a lone wolf.

Police said the gunman was not a local man and the FBI believe he may have ‘leanings to radical Islamic terrorism’.

The killings took place less than four miles from where The Voice singer and YouTube star Christina Grimmie, 22, was shot dead at The Plaza Live in Orlando on Friday.

Scroll down for video 

There was thought to be at least one hostage locked in a bathroom with gunshot wounds

There was thought to be at least one hostage locked in a bathroom with gunshot wounds

Eyewitnesses described the gunman having a bomb strapped to himself when he started shooting at around 2.00 local time (7am GMT) today 

Eyewitnesses described the gunman having a bomb strapped to himself when he started shooting at around 2.00 local time (7am GMT) today

The Pulse Club in Orlando told around the 100 revellers inside that 'everyone [should] get out of pulse and keep on running' as the man took hostages

The Pulse Club in Orlando told around the 100 revellers inside that ‘everyone [should] get out of pulse and keep on running’ as the man took hostages

Orlando Police confirmed the shooter was dead and that they were dealing with a 'mass casualty situation' 

Orlando Police confirmed the shooter was dead and that they were dealing with a ‘mass casualty situation’

Party-goers were urged to ‘get out and keep running’ as bullets started flying at around 2am local time.

Eyewitnesses described the gunman having a bomb strapped to himself when he started shooting today.

At around 6.00 local time (11am GMT) police said on Twitter: ‘Pulse Shooting: The shooter inside the club is dead.’ Officers described it as a ‘mass shooting’.

One man who said he was inside the club posted that the shooting broke out around 2 a.m. and that he heard about 40 shots being fired.

Police earlier carried out an controlled explosion at 5.15 local time (10.15am GMT today). but it is not yet clear whether that was linked with the gunman’s death.

It was thought that at least one hostage had been locked in a bathroom with gunshot wounds.

Around 100 officers were involved in the hostage situation before the gunman was killed.

Local TV reporter Stewart Moore said that more than 20 people had been shot with an assault rifle.

Jon Alamo said he was at the back of one of the club’s rooms when a man holding a weapon came into the front of the room.

Full Story