Australia vowed stricter gun laws on Monday as it began mourning victims of its worst mass shooting in almost 30 years, in which police accused a father-and-son duo of killing 15 people at a Jewish celebration at Sydney’s famed Bondi Beach.

The incident has raised questions about whether Australia’s gun laws, among the toughest in the world, need an overhaul, with police saying the older suspect had held a firearms license since 2015, along with six registered weapons.

Prime Minister Anthony Albanese said his cabinet agreed to strengthen gun laws and work on a national firearms register to tackle aspects such as the number of weapons permitted by gun licences, and how long the latter are valid.

“People’s circumstances can change,” he had told reporters before the cabinet met. “People can be radicalised over a period of time. Licences should not be in perpetuity.”

Of the two gunmen, the 50-year-old father was killed at the scene, taking the tally of dead to 16, while his 24-year-old son was in critical condition in hospital, police told a press conference.

The 40 people taken to the hospital after the attack included two police officers in serious but stable condition, they added. The victims were aged between 10 and 87.

Police did not release the suspects’ names. Security officials said one was known to authorities but had not been deemed an immediate threat.

“We are very much working through the background of both persons. At this stage, we know very little about them,” New South Wales Police Commissioner Mal Lanyon told reporters.

National broadcaster ABC and other media identified the men as Sajid Akram and his son Naveed Akram. Home Minister Tony Burke said the father arrived in Australia in 1998 on a student visa, while his son is an Australian-born citizen.

Police gave no details of their firearms, but videos from the scene showed the men firing weapons that appeared to be a bolt-action rifle and a shotgun.

Two flags of the militant group Islamic State were found in the gunmen’s vehicle, ABC News said, without citing a source.

Albanese said measures being considered ranged from curbs on open-ended licences to limits on weapons held by a single individual and the types that are legal, including modifications, with permits restricted to Australian citizens.