A special unit of Australia’s counterterrorism police detained seven men in Sydney on Thursday on suspicion of planning a “violent act,” saying that they may have been on their way to Bondi Beach, where a mass shooting left 15 people dead at a beachside Hanukkah celebration on Sunday.

The authorities have made no connection between the men and the Bondi killings “at this point in time,” the police for the state of New South Wales said on Thursday. But on Friday morning, Deputy Commissioner Dave Hudson of the New South Wales police said the men were believed to share “extremist Islamic ideology” with the suspects in the Bondi killings.

“We have some indication that Bondi was one of the locations they might be visiting yesterday, but with no specific intent in mind or proven at this stage,” Mr. Hudson said in an interview with ABC Radio Sydney.

The seven men were detained after the Tactical Operations Unit of the New South Wales police intercepted two cars in the southwest Sydney neighborhood of Liverpool. The men are now “assisting police with their inquiries,” the police said.

In his interview, Mr. Hudson said no weapons apart from a knife had been found in the cars.

Local news outlets reported that the cars had been on their way to Bondi and had license plates from Victoria, the state bordering New South Wales. The police did not confirm those details to The New York Times on Friday or explain why the authorities believed they may have been planning a violent act.

Video footage of the police operation published by The Sydney Morning Herald and Nine News showed heavily armed security forces restraining men with zip ties near a busy shopping center before they were taken into custody.

Information about the identities of the men, or whether they had been charged with any crimes, was not immediately available.

Officials have classified the attack on Sunday, the worst mass shooting in Australia in nearly three decades, as a terrorist act.

The authorities have said that the two men believed to have carried out the attacks — Naveed Akram, 24, and his father, Sajid Akram, 50 — appeared to be motivated by antisemitism inspired by the Islamic State. The police said officers shot both men; the father died, and the son is hospitalized and has been charged in the attacks.

On Thursday, Prime Minister Anthony Albanese announced new measures against antisemitism, including laws that would “crack down on those who spread hate, division and radicalization.”