Admiral Dennis Blair's testimony comes two days after the incident in which the Pentagon says five Chinese vessels harassed a U.S. Navy research ship in international waters.
China says the United States violated international and Chinese laws, saying the U.S. vessel entered China's so-called Exclusive Economic Zone (EEZ) without Beijing's permission.
The United States argues that military vessels from other countries do not need to seek permission to carry out activities in a coastal state's Exclusive Economic Zone.
Admiral Blair says the incident highlights the more aggressive military stance China has assumed in recent years.
"In the past several years, they have become more aggressive in asserting claims for the EEZ, which, as you pointed out, are excessive under any international code," he said. "This latest incident with fishing vessels and [U.S.] navy vessel involved is the most serious we have seen since 2001."
In the April 2001 incident, a U.S. surveillance plane collided with a Chinese military jet off Hainan, killing the Chinese pilot and forcing the U.S. plane to land on the island.
Meanwhile, the director of the Defense Intelligence Agency, Lieutenant General Michael Maples, told the Senate Armed Services Committee that China is strengthening its ability to conduct military operations along its periphery.
"It is building and fielding sophisticated weapon systems and testing new doctrines that it believes will allow it to prevail in regional conflicts," he said.
Maples said China is also acquiring sophisticated air defenses from Russia.
"China, from the air defense standpoint, has developed a very modern, layered, defense capability in depth, and is seeking additional defense capabilities that will project out to a range of 400 kilometers," he said. "It significantly affects potential U.S. operations in the region. Russia, quite frankly, is the developer of most of those systems."
While the United States may be wary of China's military escalation, it welcomes China's contributions to anti-piracy efforts off the coast of Somalia.
"It seems a good positive use of Chinese military forces as part of a group who are seeking common good," Admiral Blair said. "I think the debate is still on in China, as their military power increases, whether it will be for good or for pushing people around."
On a separate issue, Blair said Iran lacks weapons grade highly-enriched uranium and has not made a decision whether to convert low-grade uranium that it is making to the weapons-grade material.
Published with the permission of Voice of America
