Brisbane, Jan 2 : Four people were killed and three others are currently in critical condition after two helicopters on Monday collided at the Gold Coast in the Australian state of Queensland, authorities have confirmed. "At about 2 p.m. today, police and emergency services were called to a two-helicopter midair collision just opposite Sea World in the Broadwater. Those two aircraft then collided, have crashed and landed on the sandbank just out from Sea World resort," Queensland Police South Eastern Regional Duty Officer Gary Worrell told reporters. According to the office, one airframe had its windscreen removed and landed safely on the island, while the other crashed and turned upside down, reports Xinhua news agency. "Four people have lost their lives today and we have three others who are critical in hospital," he said, adding that the investigation is still ongoing and there will be a report for police by the coroner. Jayney Shearman, senior operations supervisor at the Queensland Ambulance Service, said that they identified 13 people in total from the two helicopters. There were also six other people suffering minor injuries mainly from glass shrapnel, according to her. Australian Transport Safety Bureau (ATSB) Chief Commissioner Angus Mitchell announced in a statement that the bureau has commenced a transport safety investigation into the fatal mid-air collision. "The ATSB anticipates publishing a preliminary report detailing basic information gathered during the investigation's evidence collection phase in approximately 6-8 weeks," Mitchell said. Meanwhile, the state's premier Annastacia Palaszczuk expressed her condolences on her social media, regarding the crash as "an unthinkable tragedy". "My deepest sympathies are with each of the families and everyone affected by this terrible accident," the state premier wrote. /IANS