A U.S. Defense official said it is likely the U.S. Navy will make more patrols near islands claimed by China and other countries in the South China Sea.
Speaking with VOA Tuesday, the official, who did not want to be identified, said, "This is not going to be the last one."
He added there were several Chinese vessels operating in the vicinity of the USS Lassen, with one of the vessels clearly "shadowing it" as it passed within 12 nautical miles (22 kilometers) of a small reef that China has been expanding into a larger island through large-scale dredging operations.
"All maneuvers by Chinese vessels and aircraft were safe and professional," according to the official.
He added it is "quite typical" for a Chinese vessel to shadow a U.S. vessel when its operating in the South China Sea. "It is not out of the ordinary," the official said.
China denounced the U.S. patrol, declaring is was dangerous "brinkmanship" in waters that carry half the entire world's cargo, worth more than $5 trillion a year.
The foreign ministry in Beijing, which said the USS Lassen "illegally entered" Chinese waters, summoned U.S. Ambassador Max Baucus Tuesday to deliver a formal protest.
Military officials in Washington said the approach to the Chinese-held Subi reef was a "freedom of navigation" exercise that is not related to questions of sovereignty over islands that also are claimed by Vietnam and the Philippines.
McCain: Long overdue
In Washington, Senator John McCain, a decorated war hero who served in the Navy and was held prisoner during the Vietnam War, said the U.S. naval maneuver was a long-overdue gesture.
"As China mounts increasingly routine challenges to the freedom of the seas through the Asia-Pacific region," McCain said, "it is more important than ever that the United States fly, sail and operate wherever international law allows. And the South China Sea must be no exception."
He called for regular air and naval patrols in the weeks and months ahead to make clear "the U.S. commitment to uphold freedom of the seas."
U.S. allies in the region also welcomed the American ship's passage near the disputed Spratly Islands, although in more cautious terms.
In Manila, Philippines, President Benigno Aquino said, "Any movement through this particular body of water should not be hampered by any particular entity.”
Japan said it continues to be concerned about China's activities in disputed territories and waters.
“We're closely coordinating our intelligence information with the United States,” Chief Cabinet Secretary Yoshihide Suga said in Tokyo.
Vietnam has not yet commented on the matter.
Nguyen Ngoc Truong, a former Vietnamese diplomat and currently chairman of privately owned Center for Strategic Studies and International Development, said Hanoi has to calculate carefully how to respond so as not to anger its giant northern neighbor China.
“Vietnam’s silence means agreement [with what the U.S. is doing]. Vietnam shared thousands of kilometers of border with China so it has to be careful with its response. It does not want to complicate its relations with China," Truong said.
Class: Arleigh Burke missile destroyer, among the most powerful destroyers ever built
Size: 155 meters (509 feet) long with a displacement of about 9,200 tons when fully loaded
Armament, defenses: Includes two Seahawk helicopters; Tomahawk missiles, RUM-139 Asroc anti-submarine missiles and surface-to-air missiles; uses the Aegis defense system
Speed: 30 knots
Namesake: Lieutenant Clyde Everett Lassen, the first naval aviator and fifth Navy winner of the Medal of Honor for bravery in Vietnam
Crew: about 320
Homeport: Yokosuka, Japan
Source: U.S. Navy
"I think the U.S. understands the stance of Vietnam as well as the latter’s strategic location. It is in a difficult and delicate position, facing huge pressure from China," he said.
American officials had indicated weeks ago that the Navy would send a ship into the disputed territorial waters.
About 200 Chinese troops are believed to be stationed on the Subi reef, which is naturally above water only at low tide.
Action was expected
Sheila Smith, senior fellow for Japan studies at the Council on Foreign Relations in Washington, said the U.S. naval activity had been expected.
China's reaction, Smith noted, suggests "that they are not ready to peacefully resolve these disputes but, in fact, their buildup and the presence of Chinese military on these islands suggests that they want a fait accompli. They just simply want to occupy the islands.”
Other claimants to the South China Sea islands cannot compete with China's growing naval and air power, she said, adding, “I don't think the United States should stand back," because the Americans have "one of the navies ... that others in the region look to – to set the tone and to lead."
Steve Herman in Bangkok, Bill Ide in Beijing, Simone Orendain in Manila and Trung Nguyen in Washington contributed to this report.