The US has expressed worries over China's military plans and urged Beijing to clarify the intentions behind its military buildup.

The US military's Asia-Pacific Commander Admiral Timothy Keating, in his second official visit to China, urged Beijing to increase transparency in military affairs during talks with government and defense officials which focused largely on the issue of Taiwan.

Keating told journalists Tuesday that Chinese military is developing "impressive capabilities" and the US was concerned about long-range cruise and ballistic missiles, as well as anti-satellite technology and its use.

He also said that increased transparency can yield to greater trust and reduces the potential for misunderstanding which can lead to conflict or crisis.

On Monday Beijing agreed to bring military exchanges with the US to a higher level, a form of cooperation that could help allay growing concerns over the intentions behind China's military build-up.

Keating accompanied by Assistant US Secretary of Defense James Shinn and other US officials met Monday with Chinese Foreign Minister Yang Jiechi and General Guo Boxiong, vice chairman of the powerful Central Military Commission.

On the other hand, China reiterated its concern over US weapons sales to Taiwan, which it fears is emboldening independence forces there, China's Foreign Ministry said.

According to the Taiwan government, China has increased the number of ballistic missiles facing the island to over 1,000 in recent years.

China considers Taiwan part of its own territory awaiting reunification and has threatened to attack the island if Taipei seeks a permanent independence.