China on Wednesday expressed concern over a security agreement signed by the United States and Australia, saying that a military alliance between the two countries “may not be in the interest" of the region.

In Canberra, United States President Barack Obama and Australian Prime Minister Julia Gillard on Wednesday announced a new security arrangement, under which 250 U.S. Marines would be stationed, on rotation, in Australian bases in Darwin and northern parts of the country.

Under the agreement, which the two leaders said would help maintain security in the Asia-Pacific region, the number of personnel would subsequently be expanded to 2,500, Ms. Gillard said.

Mr. Obama said the agreement reflected the U.S. “stepping up” its commitment to the Asia-Pacific, and was not, as many analysts have said, targeting China.

"I think the notion that we fear China is mistaken,” he said. “The notion that we’re looking to exclude China is mistaken.”

In Beijing, Chinese Foreign Ministry spokesperson Liu Weimin said: “It may not be quite appropriate to intensify and expand military alliances and may not be in the interest of countries within this region.”

"Whether strengthening and expanding a military alliance is in the common interests of the region and the international community,” he added, “is worthy of discussion.”

"As for using the form of a military alliance, China has its own concepts of friendly cooperation with all countries. China never engages in military alliances.”

Mr. Liu, however, added that the Chinese government did not see the agreement as a move to contain China. “President Obama and other U.S. officials have said time and again that the U.S. welcomes a China that is strong and prosperous,” he said. “Therefore, they have no intention of containing China. We hope the U.S. will keep to its words.”

The Communist Party-run Global Times, a nationalistic tabloid, took a stronger view of the military deal, warning that Australia risked harming economic ties with China, the country's largest trade partner and the biggest destination for Australia's thriving exports of minerals.

"Apparently, Australia aspires to a situation where it maximises political and security benefits from its alliance with the U.S., while gaining the greatest economic interests from China," the paper said.

"However, [Australian Prime Minister Julia] Gillard may be ignoring something - their economic cooperation with China does not pose any threat to the U.S., whereas the Australia-US military alliance serves to counter China."

"Australia surely cannot play China for a fool," the newspaper added, warning that "if Australia uses its military bases to help the U.S. harm Chinese interests, then Australia itself will be caught in the crossfire."