The first wave of U.S. Marines has arrived in northern Australia, marking the start of a larger U.S. military presence in the Asia-Pacific region.

Australian Defense Minister Stephen Smith greeted the 200 Marines as they stepped off a charter flight in Darwin Wednesday. The Marines are the first contingent of an eventual 2,500-member Air Ground Task Force that will engage in joint military exercises with Australian forces.

Under the agreement, Australia also will facilitate an increased use of Darwin air base by U.S. military aircraft, including jet fighters and bombers.

Jeffrey Bleich, the U.S. ambassador to Canberra, says it is fortunate that U.S. forces are stationed in the region, which he described as “the most dynamic area in the world right now.”

“This is the fastest growing economic area and also the one that is enduring the greatest demographic change, and we want to make sure that it continues to be a peaceful, prosperous and stable area. The way that we accomplish that is by ensuring that trade routes are open and that we're prepared for any issue that could come up and so the opportunity to train here in Darwin is ideal for having the ability to do that. You have access the Pacific Ocean, to the Indian Ocean, to the East Timor Sea and to trade routes all around.''

The Marines will not establish a permanent outpost in Darwin. Instead, they will be based at a military barracks on the city's outskirts and deploy to the region on a six-month rotational basis.

The deployment is part of an agreement announced in November by U.S. President Barack Obama and Australian Prime Minister Julia Gillard during events marking the 60th anniversary of the two nations' military and strategic alliance.

The agreement was met with open suspicion by China, which fears the U.S. seeks to stifle Beijing's rise as a global economic and military power. But the Australian defense chief says the U.S. military presence will help to ensure peace and security in the region.

“This region and the world is in a state of flux, and the international community needs to respond to that and to seek to try and manage that change in strategic flux and that's why for example, the bilateral relationship between the United States and China is I believe the most important bilateral relationship that we'll see in the course of this century. Followed very closely by the bilateral relationship between United States and India, and the bilateral relationship between India and China. Over the sweep of history there are always changes in economic influence, strategic influence, political influence and indeed military influence, and the world needs to adjust to that. We are absolutely confident that we can emerge through this changing period in a stable state, in a state where peace and security continues in the Asia Pacific region. But also in a state where prosperity continues to be seen very vividly through our region.''

The growing American presence in Asia-Pacific could potentially worsen what two scholars — one American, the other Chinese — describe in a recent study as a long-term “strategic” distrust between Washington and Beijing. But Australian scholar Jonathan Blaxland, tells VOA the new posture will have a minor impact on bilateral U.S.-China relations.

“My sense is that the level of distrust between China and the United States is at a steady state. This is really, relatively speaking, a minor redeployment of troops. The number of Marines operating in the western Pacific is not increasing, it's simply a rearrangement of current deployments, and this is really quite a long way away from China. And the other thing to bear in mind is, this is Australia's prerogative. We can host in our country, whoever we invite to come in, and the United States Marine Corps is very welcome.”

News reports say Australia may allow the U.S. to use the northern territory to operate long-range unmanned spy planes.