Shocking new details emerge over Bondi Beach shootings including 'tennis ball bombs'

Details revealing the preparation of the two alleged gunmen charged with carrying out a terrorist attack at Australia's Bondi Beach have been revealed by police.

On 14 December, Sajid Akram and his son Naveed allegedly opened fire on a group of worshippers gathered at Sydney's iconic beach to mark the beginning of the Jewish festival of Hanukkah.

A total of 15 people were killed in the attack, the youngest being a 10-year-old girl, with several more people injured.

Sajid was shot and killed by police at the scene, while 24-year-old Naveed was taken to the hospital after being critically wounded.

He has since been charged with 59 separate offences in relation to the attack, which includes 15 counts of murder, 40 counts of grievous bodily harm with intent to murder, public display of a terrorist symbol and placing explosives with intent to cause harm.

Further details regarding the Bondi Beach attack have been released as police build their case (Izhar Khan/Getty Images)

He remains in hospital under police guard and has not been required to attend a court hearing on the case.

New details regarding the case have since been released by New South Wales Police, alleging that the father-and-son had 'meticulously planned' their attack for several months and had been motivated by 'violent extremist ideology' linked to the Islamic State, a group which is deemed a terrorist organisation in Australia.

Police have also alleged to have CCTV footage showing the men carrying numerous 'long and bulky items wrapped in blankets' out of rented accomodation on the day of the attack, which were later placed in their car.

These items are said to include the three homemade explosives, including a 'tennis ball bomb', and firearms used in the attack.

Evidence shared by New South Wales Police includes an explosive found the the Akram's car (NSW Police)

The explosive devices were allegedly thrown during the attack, but did not detonate. Police later found a fifth explosive device and two IS flags in the car.

Further CCTV footage is said to show the men driving to the area in the days leading up to the attack to conduct reconnaissance on 12 December.

"The Accused and his father, S Akram, are seen to exit the vehicle and walk along the footbridge, being the same position where they attended two days later and shot at members of the public," reads a police note on the footage (via News.com.au).

"Police allege that this is evidence of reconnaissance and planning of a terrorist act."

Police also believe they've found evidence of the men performing firearms training (NSW Police)

Meanwhile, videos recovered from Naveed's phone are said to evidence claims the pair were motivated by 'violent extremist ideology'. This includes a clip showing the pair sitting in front of an IS flag and declaring their motivations for the attack.

Another video allegedly depicts the men conducting firearms training back in October in what police suspect to be rural South Wales, the BBC reports.

"The Accused and his father are seen throughout the video firing shotguns and moving in a tactical manner," police claimed.