Multiple casualties reported and hostages taken by gunman in Orlando gay club

Multiple casualties are feared after a gunman opened fire and barricaded himself inside a gay club in Orlando, Florida.

Orlando police confirmed that multiple people had been injured and urged people to stay away from the area. 

The gunman entered Pulse at approximately 2am local time armed with an assault rifle. 

On its Facebook page, the nightclub said: "Everyone get out of pulse and keep running."

A witness told Sky News that more than 100 people were in the club. "We just heard shots, it was less than a minute, it felt longer," he said. 

Local news anchor Stewart Moore tweeted saying more than 20 people have been shot, and that the attacker may have been wearing a bomb, although this has not been confirmed.

This is a breaking news story and will be updated as more information comes in.