Sydney: Australia and the United States launched a massive war game on Monday aimed at honing their ability to act together against threats to Asia-Pacific security, commanders said.

More than 20,000 US troops and 12,000 Australians, backed by a total of 30 ships and 125 aircraft, will be involved in "Operation Talisman Sabre 2007" on the northeast coast until July 2. Vice Admiral Doug Crowder, commander of the US Navy's 7th Fleet, said uncertainty and unpredictability remained a threat to economic prosperity in the Asia-Pacific region.
"Therefore it is very important that our militaries train together to carry out the types of missions our governments may call upon us to execute to ensure regional security and stability. "Thats exactly what Talisman Sabre 2007 is all about, further developing our ability to operate together as a combined military force," Crowder told reporters aboard the USS Blue Ridge command ship in Sydney.

Australia's Major General Richard Wilson said the operation was the country's largest military training exercise. "Talisman Sabre is based on a fictional scenario that combines most of the difficult aspects of modern warfare operations," he told reporters.

The war game will involve parachute regiments and amphibious forces paving the way for land-based attacks, along with a series of land, sea and air exercises from bases at Rockhampton and Townsville in Queensland state.

Australian Prime Minister, John Howard, is a close ally of US President George W. Bush and has contributed troops to US-led operations in both Iraq and Afghanistan.