A manhunt is underway for four men who rained terror on a packed cinema by storming inside screaming 'Allahu Akbur.'

Witnesses say one man burst inside the Blacktown cinema in Sydney's west chanting the battle cry of Islamic jihadists committing mass murder.

The man then left and returned with three other men to continue chanting the Arabic phrase, leaving movie-goers fearing an impending attack, 9News reported.

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Witnesses were horrified when four men burst inside the Blacktown cinema (pictured) screaming 'Allahu Akbur'

The men are described by police as being of Middle Eastern appearance, each with a beard, in their 20s and wearing dark clothing.

A NSW Police spokesperson confirmed to Daily Mail Australia they searched the cinemas after reports of the intrusion.

'Officers searched the cinema and found nothing suspicious, however they are now investigating the circumstances,' the spokesperson said.

Police are calling on anyone with footage or images of the incident to come forward in the hope of tracking down the men.

Movie-goers have told of their horror at an impending attack inside the cinema

A Hoyts spokesperson told Daily Mail Australia they were assisting police with their investigation but could not comment further.

The incident comes amid heightened tensions in Australia after a series of ISIS-inspired attacks recently including a deadly siege last week.

Police shot dead gunman Yacqub Khayre in the city of Melbourne after he killed a man in an apartment block and held a woman hostage for several hours.

The Federal Government is reviewing police tactics and the powers of state and federal authorities to crackdown on the threat of terrorism.

The NSW government is also planning Australia's first prison aimed at isolating militants and stopping the spread of radical beliefs through the prison system.