Bondi gunmen were motivated by Islamic State and had traveled to the Philippines, Australian police.

SYDNEY (Reuters) — Two suspected shooters who attacked a Hanukkah gathering on Sydney’s Bondi Beach had been to the Philippines prior to the incident, which murdered 15 people and appeared to be inspired by Islamic State, authorities said on Tuesday.

The incident on Sunday was Australia’s deadliest mass shooting in over 30 years, and it is being investigated as a terrorist act against the Jewish community.

The dead toll is 16, including one of the suspected gunman, identified by authorities as Sajid Akram, 50, who was shot by officers. The man’s 24-year-old son and suspected collaborator, Naveed Akram, was also wounded and is in serious condition in the hospital.

Australian police said on Tuesday that both men traveled to the Philippines last month, and the reason of their trip is being investigated. Police in the Philippines have stated that they are investigating the situation.

Islamic state-linked networks are known to operate in the Philippines, and they have had some impact in the country’s south. They have been reduced to weaker cells operating in the southern Mindanao island in recent years, a far cry from the power they possessed during the 2017 Marawi siege.

“Early indications point to a terrorist attack inspired by Islamic State, allegedly committed by a father and son,” Australian Federal Police Commissioner Krissy Barrett said during a press conference.

“These are the alleged actions of those who have aligned themselves with a terrorist organisation, not a religion.”

According to police, the car belonged to the younger individual had improvised explosive devices and two handmade flags connected with ISIS, or Islamic State, a militant group recognized as a terrorist organization by Australia and many other nations.

The father and son allegedly opened fire on hundreds of people at the festival during an approximately 10-minute killing spree at one of Australia’s most popular tourist sites, prompting thousands to escape and seek refuge until both were slain by police.

Approximately 25 survivors are undergoing treated in multiple Sydney hospitals, authorities said.