Authorities detains 7 men suspected of trying to join militants

Authorities have detained seven young Australian men as they were attempting to fly to the Middle East, Prime Minister Tony Abbott said on Thursday, over suspicions they wanted to join militant Islamist groups.

Australia is on high alert for attacks by radicalised Muslims, including home-grown militants returning from fighting in the Middle East. It has raised its threat level to "high" and unleashed a series of high-profile raids in major cities.

Besides guarding against any domestic attacks, Australian officials have stepped up efforts to keep radicalised citizens from joining organisations such as the Islamic State militant group that has seized large areas of Iraq and Syria.

Five men in their 20s and 30s were stopped from flying out of Sydney airport last week to an undisclosed location, Australian Border Protection Minister Peter Dutton told reporters.

Each of the five was found to be carrying about A$10,000 ($7,347) when his luggage was searched, he said.

Two more men were stopped when they attempted to board a flight from Sydney at the weekend. Dutton said those two had connections with the five men detained earlier.

The Australian Federal Police told Reuters no charges have yet been laid against the seven detained men.

Abbott has told parliament at least 70 Australians were fighting in Iraq and Syria, backed by about 100 Australia-based "facilitators".

"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," Dutton said on Thursday. ($1=1.3611 Australian dollars)