VIENNA — Investigators in several Austrian regions carried out raids early Monday on people and organizations suspected of supporting the Muslim Brotherhood and Hamas groups, prosecutors said.

Authorities said there was no link between Monday's action against suspected Islamic radicals and the attack in Vienna a week ago in which an assailant — described by officials as a supporter of the Islamic State group — fatally shot four people before being shot and killed by police.

But the shooting has strengthened calls in Austria for a crackdown on Islamic extremism.

Prosecutors in Graz said more than 70 people are under investigation in the new case and 60 properties, including apartments and offices, were searched, the Austria Press Agency reported. Thirty people were taken in for questioning.

Prosecutors said they are looking into suspicions of terror financing, criminal organization and money laundering among other offenses. They said the raids resulted from more than a year of investigations.

Austrian Chancellor Sebastian Kurz, speaking later Monday after a meeting with European Union leader Charles Michel, said his country wants a coordinated, Europe-wide effort to tackle Islamic extremism in the wake of last week's attack.

This includes combating political Islam, which he described as "the ideology behind the aggression toward our society, toward our way of life."

Kurz also called for a "robust approach" against foreign fighters who have tried, successfully or not, to join extremist militias in Syria, Iraq and elsewhere.

"They are simply ticking time bombs and therefore a threat to our societies," he said.

"And third, we naturally need proper protection of the EU's external borders," said Kurz, a longtime critic of mass immigration.

"Only if the European Union can decide who immigrates and who doesn't, only if we control who enters the European Union or not, will we be able to safeguard security," he said.