SKY NEWS:- Islamic State has claimed responsibility for the Orlando nightclub shooting which killed 50 people and injured 53 others. according to the Amaq news agency.

A statement carried by the Amaq news agency, which is tied to IS, said the mass shooting was “carried out by an Islamic State fighter”.

The attack is the deadliest mass shooting in US history, eclipsing the 2007 Virginia Tech massacre which left 32 people dead.

The claim comes after it emerged that the suspect Omar Mateen swore allegiance to IS in a 911 call he made just before the attack.

Officials have cautioned that the alleged links between the 29-year-old gunman and IS need to be investigated further.

He was armed with a device thought to be a bomb, an assault rifle and a handgun, when he opened fire in the gay nightclub Pulse on Sunday morning before taking hostages.

He was involved in a three-hour stand-off with officers before SWAT teams stormed the building and shot him dead.

President Barack Obama has condemned the massacre as an “act of terror and an act of hate”.

Orlando Mayor Buddy Dyer said: “We’re dealing with something that we never imagined and is unimaginable. There’s blood everywhere”.

He said a state of emergency has been declared in the city of Orlando and that he has asked Florida’s governor to issue a state-wide state of emergency due to the “scale of the crime”.

In a statement House Homeland Security Chairman Michael McCaul said: “This appears to be the worst terrorist attack on American soil since 9/11, and it is a sobering reminder that radical Islamists are targeting our country and our way of life.”

However, US Congressman Alan Grayson told reporters there is currently no “direct information” to suggest the gunman was directly associated with any particular group.

He told Sky News authorities are investigating whether the attack was a “hate crime perpetrated against gays”.

The gunman’s father also told US media the attack may have been triggered by the sight of a gay couple kissing in Miami, adding that it had “nothing to do with religion”.

“He saw two men kissing each other in front of his wife and kid and he got very angry,” Mir Seddique told NBC News.

The attack unfolded just after 2am when an officer working as a security guard at the club raised the alarm and engaged in a gunbattle with Mateen. The gunman then took a number of hostages inside the popular gay club.

Some clubbers mistook the sound of gunshots for music and the bar posted on its Facebook account: “Everyone get out of pulse and keep running.”

A mother has told how her son texted her from the club toilets where he was hiding, telling her “I’m gonna die” and “Mommy I love you” before a final text saying: “He’s coming”.

Congressman Grayson told Sky News there was “some communication” between police and the gunman during the ensuing standoff.

“They (police) tried to coax him out and release the hostages at the same time as they were summoning the forces that they needed in order to go in and end the situation with the minimal loss of life.”

At 5am police launched a mission to rescue the hostages and 11 officers stormed the club, shooting dead the attacker following a short gunfight.

One officer was shot in the head but his Kevlar helmet saved his life.

A surgeon at Orlando Regional Medical Centre has warned that the death toll is likely to climb.

Hundreds of people have lined up outside health centres to give blood to help the victims.