Deepening engagement between Australia and the United States will be discussed at high-level talks in Sydney on Tuesday, with analysts saying it could lead to a greater American military presence Down Under.

Flags flew at half mast Thursday as Australia held a national day of mourning for those killed in the MH17 crash in Ukraine, a day after experts suspended the search for body parts.

Australia lost 38 citizens and residents, including children, when the Malaysia Airlines plane from Amsterdam to Kuala Lumpur was shot down over eastern Ukraine on July 17, killing all 298 on board.

A Dutch firm will conduct a deep-water search in the Indian Ocean for missing Malaysia Airlines Flight MH370 from September, Australia said on Wednesday, expressing "cautious optimism" that the plane will be found.

Fugro Survey will use its state-of-the-art vessel MV Fugro Equator and the Fugro Discovery to search a 60,000 square-kilometer (23,000 square-mile) zone in the southern Indian Ocean.

Australian Prime Minister Tony Abbott on Wednesday defended tough new terror laws under which Internet data, including websites browsed, will be retained, denying it is an invasion of privacy.

The government plans to overhaul laws to make it easier to arrest and prosecute terrorists and make it an offense to travel to designated hotspots overseas without a valid reason.

Australia's immigration detention system was a toxic environment akin to torture, according to the chief psychiatrist for asylum-seekers for the past three years, a report said Tuesday.

Australia will toughen laws to target home-grown terrorists and those who fight overseas over fears violent jihadist citizens in Syria and Iraq will return home, officials said Tuesday.

Some 25 delegates to an international AIDS conference held in Melbourne last month fear returning home and will seek asylum in Australia, refugee and welfare agencies said Monday.

HomeGround Services, which helps find crisis accommodation for homeless people in Melbourne, said 14 delegates from African nations -- including Uganda and Tanzania -- had sought their help.

Top U.S. diplomat John Kerry will travel to Myanmar, Australia and the Solomon Islands later this month, the State Department said Saturday.

The August 8 to 13 trip will kick off in the Myanmar capital of Naypyitaw on August 9 where Kerry will meet government leaders and attend a series of gatherings, including the ASEAN Regional Forum and East Asia Summit ministerial.

Some 157 asylum-seekers who were detained at sea for weeks by Australia have been sent to the Pacific island of Nauru after rejecting a return to India, officials said Saturday.

Australia's human rights commissioner said Thursday the government must come clean about conditions at offshore asylum-seeker camps after an inquiry heard of an alleged cover-up of mental health problems.