(Adds quotes, details from border protection minister, paragraphs 3-5, 7-8)
By Colin Packham
SYDNEY, Aug 20 (Reuters) - 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.
"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 in Canberra.
Five men aged in their 20s and 30s were prevented from flying out of Sydney airport last week to an undisclosed location, Australian Border Protection Minister Peter Dutton told reporters.
Each of the five were found to be carrying about A$10,000 ($7,347) when their luggage was searched, he said.
Another two 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.
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.
In addition to attempts to safeguard against any domestic attacks, Australian officials have intensified efforts to prevent radicalised citizens from joining organisations such as the Islamic State militant group that has seized large areas of Iraq and Syria.
"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.
Abbott has told parliament at least 70 Australians were fighting in Iraq and Syria, backed by about 100 Australia-based "facilitators".
($1 = 1.3611 Australian dollars)