China's military has made dramatic progress in space over the past decade and the goals of its program remain unclear, a top American general said on Tuesday.

Citing Beijing's advances in space, General Kevin Chilton, head of US Strategic Command, said it was crucial to cultivate US-China military relations to better understand China's intentions.

"With regard to China's capabilities, I think anyone who's familiar with this business -- and particularly our history in this business over the years -- would have to be absolutely amazed at the advancement that China has made in such a short period of time, whether that be in their unmanned program or the manned program," Chilton told reporters in a teleconference, referring to Beijing's space program.

"They have rapidly advanced over the last ten years," he said from Omaha, Nebraska.

"Where they're heading I think is one of those things that a lot of people would like to understand better, what their goals and objectives are. But they certainly are on a fast track to improve their capabilities," he said.

Chilton's comments came after a top Chinese air force commander, Xu Qiliang, called the militarization of space a "historical inevitability" and said that the country's military was developing offensive and defensive operations in space.

The Chinese commander's remarks, reported by state media on Monday, marked an apparent shift in Beijing's opposition to weaponizing outer space.

Chilton acknowledged that space had become an arena for military rivalry, with an increasing number of countries pursuing space-based weaponry -- including Iran and North Korea.

"Clearly, I think what we've all come to understand is that space is a contested domain. It used to be looked at like a sanctuary. And clearly that's not the case today," the air force general said.

Asked about the Chinese commander's remarks, Chilton said that Beijing's space program "is an area that we'll want to explore and understand exactly what China's intentions are here, and why they might want to go in that direction and what grounds might accommodate a different direction."

A Republican member of Congress adopted a tougher tone, criticizing China for pursuing space weapons and for shooting down a weather satellite in 2007.

"Despite public declarations to the contrary, Beijing's continued investment in anti-satellite technologies and yesterday's revelation by a senior Chinese military official, demonstrate a clear intent to pursue offensive space capabilities," Representative Michael Turner of Ohio said in a statement.

When President Barack Obama visits China in a tour of Asia this month, he should "pressure Chinese officials to provide greater transparency regarding their intentions for the development, test, and deployment of anti-satellite weapons," Turner said.

In January 2007, China shot down one of its own weather satellites in a test seen by the United States and others as a possible trigger of an arms race in space.

Turner said Obama should make clear to Beijing that further anti-satellite tests would be "irresponsible and unacceptable."

Chilton said a visit last week to Strategic Command headquarters by General Xu Caihou, China's second-ranking military officer, marked a promising step in efforts to promote more dialogue with Beijing.

"I think maybe through dialogue we can better understand what their broader objectives are. I think that's one of the most encouraging things about the visit we had last week," he said.

US defense analysts have warned that the American military will soon lose its dominance on the high seas, in space and in cyberspace as China and other emerging powers obtain sophisticated weaponry and missiles.