A policeman stands on a street that has been blocked to the public after Australian counter-terrorism police arrested four people in raids late on Saturday across several Sydney suburbs in Australia, July 29, 2017. REUTERS/David Gray/Files

BEIRUT: Lebanon monitored the brothers accused of plotting to blow up a flight from Sydney to Abu Dhabi for more than a year and coordinated with the Australian government on it for a long time, the Lebanese interior minister said on Monday.

Australian police charged Khaled Khayat and Mahmoud Khayat this month with two counts of planning a terrorist attack after conducting raids to disrupt what authorities described as a Daesh-inspired plot to bomb an Etihad Airways flight.

Lebanese Interior Minister Nohad Machnouk told a news conference that one of the men's brothers, Tareq Khayat, had moved to the Daesh stronghold of Raqqa in Syria and become a commander in the extremist group more than a year ago.

Lebanon's Internal Security Force then placed Tareq, Khaled and Mahmoud Khayat, and Amer Khayat ? a fourth brother ? under surveillance.

Khaled, Mahmoud, and Amer were all living in Australia but occasionally visited Lebanon, he said in Beirut.

Machnouk said the brothers were Lebanese. He said Amer Khayat had arrived in Lebanon on July 15 ? the day Australian police have said the plotters tried to smuggle a bomb onto an Etihad flight from Sydney.

Australian police also said a man had tried to check in luggage without knowing that it contained a bomb, which was hidden in a meat grinder, placed there by his brother.

However, Machnouk said Amer Khayat was to have carried out the attack and that a Lebanese internal intelligence agency had found he was "involved in the operation". He said a bomb had also been hidden in a large child's doll in the luggage.

He did not say what has happened to Amer Khayat since he landed in Lebanon.

The plot was foiled because the luggage exceeded the airline's weight limit, Machnouk said.

Australian police had previously said it appeared that one of the accused had left the airport, taking the luggage with him, while his brother boarded the plane and left Australia.

On Tuesday, Australian police said it was not appropriate to comment further on the details of a current investigation that was also before Australian courts.

"We have a close and cooperative relationship with the Lebanese authorities and are working closely on this investigation," an Australian Federal Police spokeswoman said in an email.

Asked whether the operation would have been successful if the luggage had not exceeded the weight limit, Machnouk said, "Probably, yes".

He said information from Lebanese intelligence had "assisted in foiling a large operation aiming to blow up a plane".

"The [targeted] plane had 120 Lebanese on board in addition to other nationalities," Machnouk said.