Armed police stormed a Malaysia Airlines flight that was forced to return to Australia after a passenger tried to enter the cockpit claiming he had a bomb. 

"He was saying: 'I'm going to the blow the f…ing plane up, I'm going to blow the plane up,'" passenger Andrew Leoncelli told Australian Broadcasting Corp on Thursday.

"He was agitated, is the best description, 100 percent he was agitated," Leoncelli said.    

Passengers described fearing for their lives, but Malaysian Deputy Transport Minister Abdul Aziz Kaprawi said a Sri Lankan national, who appeared to have been drunk, was overpowered by passengers and crew and later arrested.    

"It is not a hijack. One disruptive passenger tried to enter the plane's cockpit," Aziz told AFP news agency.    

"The passenger... claimed to have a bomb. But it was not a bomb but a power bank. Everyone on board is safe... He was taken out of the plane handcuffed by Australian security officers."   

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Kuala Lumpur-bound Flight MH128 left Melbourne at 11:11pm (13:11GMT) on Wednesday, but turned back shortly afterwards when the man allegedly threatened those on board, Australian police said.    

Police Superintendent Andy Langdon said the suspect appeared to have a history of mental illness.      

"We do not believe this is terrorist-related at the moment," Langdon said.    

While officials tried to downplay the incident, passengers told of some 90 minutes of onboard drama and fear after take-off.    

A business class passenger, who identified himself as Andy, told Melbourne radio station 3AW the arrested man had threatened to "blow the plane up".    

"The staff screamed out 'I need some help, I need some help'. So I jumped up, undid my buckle, and approached him."    

Andy said the man ran to the back of the plane, where two other men grabbed and disarmed him of a "giant black thing" and "put hog ties on him".    

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Langdon described the experience for passengers as "very traumatic", adding passengers and crew were "heroic".    

Passenger Arif Chaudery said he joined several others to subdue the man.    

"Families, kids, they were very scared, and some screaming ... so three or four guys, we jumped as quickly as possible," he told Channel Nine.    

"We just put him on the floor, and finally staff brought the belt, so we handcuffed him and tied his legs and put his face on the floor."    

Laura, who asked for her surname to be withheld, told ABC she feared for her life.    

"I thought the plane was going to go down; I thought the bomb was going to go off. I really did think I was going to die," she said.

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Source: News agencies