CANBERRA, Australia -- Seven young Australians were recently prevented from leaving the country for fear that they intended to join terrorists in the Middle East, the prime minister said Thursday.

Prime Minister Tony Abbott refused to give details, including who the seven were, their ages, gender or where and when they were intercepted.

"We have stopped at the airport seven young Australians who were planning to travel to the Middle East, it seems, to join terrorist groups over there," Abbott told reporters.

"This indicates the continuing allure of this death cult," he said, referring to the Islamic State movement. "It shows the importance of the most vigorous action at home and abroad to disrupt, degrade, to destroy this menace to the freedom and the security of the world."

The largest single group of suspected jihadis to attempt to leave Australia for Syria and Iraq were stopped by counterterrorism authorities at Sydney International Airport on Aug. 12, The Daily Telegraph newspaper reported Thursday. That group comprised five men, the newspaper reported, citing an unnamed intelligence source.

Border Protection Minister Peter Dutton confirmed there had been "an incident" at the airport on Aug. 12, but would not provide details because an investigation was ongoing.

"I can say to you that there was an incident at Sydney International Airport on Aug. 12 and that follows a number of people who have been off-loaded by the counterterrorism unit officers in particular in Sydney and Melbourne over a period of time," Dutton told reporters.

"We are concerned about the number of people presenting at airports, particularly younger people, who might be seeking to travel overseas for reasons that would horrify Australians and their parents and family and community, no doubt, as well," he added.

Australia has posted counterterrorism units at all international airports since September last year in a bid to prevent jihadis travelling to the Middle East.