About 18,000 Chinese troops using their country's most advanced weapons systems last week rehearsed coordinated air, sea and ground attacks on Dongshan, an island in the South China Sea that resembles Taiwan in terrain and weather.

At about the same time, Taiwanese pilots 185 miles northeast landed advanced Mirage 2000-5 fighters on a blocked-off freeway to practice what they would do if their air bases were hit during a Chinese missile assault on the disputed territory.

Providing its own martial background music, the U.S. Navy staged a global readiness drill with seven carrier groups around the world to show that the United States could muster overwhelming force anywhere, including Taiwan, despite the war in Iraq.

Asia's season of concurrent military exercises reached a high point with the Dongshan maneuvers. The activity provided a reminder that, although Iraq is the main focus of military conflict for the moment, the standoff over Taiwan remains one of the world's most dangerous flash points.

The three governments involved, China, the United States and Taiwan, all insisted their military maneuvers were not timed to match those held by the others and should not contribute to the tension surrounding Taiwan. But their officials acknowledged that one purpose of holding such exercises was to demonstrate military resolve and ability to potential foes as well as friends.

China's eighth annual exercises around Dongshan Island, which lies just off the mainland's southern rim, concluded Friday after a week of activity. The government-run China Youth Daily said the exercises were intended to allow the military to practice joint combat operations and show Taiwan's independence advocates that China has the power to back up its threat to recover the island by force, if necessary.

In unusually detailed reporting on China's secretive military, the official newspaper said recently acquired Su-30 fighter jets, a Sovremenny-class destroyer and a Kilo-class submarine participated in the maneuvers. The drill, which coordinated different branches of the military, was designed to display the ability to seize air and sea dominance over Taiwan, the newspaper said.

A U.S. military official said the Dongshan maneuvers showed "some enhancements this summer that we haven't seen before" in coordinating air, sea and ground forces, but that they did not mark a startling departure from past exercises.

Taiwan's annual Hankuang exercises, which began Wednesday and are also scheduled to last a week, were unusual in that they opened with a landing by the two Mirage 2000-5s on Sun Yat-Sen Freeway in central Taiwan. According to reports from Taiwan, the landing was the first such use of the freeways since drills in the late 1970s.

Pilots operating the French-built aircraft practiced refueling and re-arming with air-to-air missiles, simulating what they would do if they were called on to combat a Chinese air attack if their normal landing facilities were destroyed. In addition, the maneuvers included practice operations against a mock Chinese amphibious landing and against an airborne attack by Chinese paratroops.

The Taiwanese maneuvers, although spectacular because of the freeway landings, seemed to have less real bearing on the island's defenses than a debate underway in the Legislative Yuan, or parliament, over a $16 million special budget allocated by President Chen Shui-bian's government for purchase of weapons from the United States. From among several weapons systems under consideration, PAC-3 advanced anti-missile defenses have been cited as the likely highest-priority purchase.

The Bush administration has pressed Chen's government to devote more resources to defense, in particular for the PAC-3 system to counter approximately 500 short-range ballistic missiles that China has deployed along its southern shore just across the 100-mile Taiwan Strait. A recently issued Pentagon report on the Chinese military estimated that the Beijing government was adding about 75 missiles a year to the array as part of a general modernization program.

The report said that China's defense spending has reached between $50 billion and $70 billion a year under the modernization program, ranking it behind only the United States and Russia. That estimate was considerably higher than the Chinese government's declared military budget for 2004, which reached $25 billion after an 11.6 percent increase from 2003.

The United States' global exercises, Summer Pulse '04, have touched the Taiwan issue peripherally, according to U.S. officials. The operation, taking place through mid-August, was designed to show "global surge capability," or the ability to use force in several places at once even with 140,000 U.S. troops locked into Iraq, according to Navy Capt. John Singley, spokesman for the U.S. Pacific Command.

Two of the seven carrier strike groups involved, the USS Kitty Hawk and the USS John C. Stennis, will conduct maneuvers in the Pacific, but not near Taiwan, Singley said.

Tao Wenzhao, deputy director of the American Studies Institute at the Chinese Academy of Social Sciences, said Chinese officials had been informed of the dimensions of Summer Pulse and were not alarmed. The subject did not arise in official conversations during a visit to Beijing last week by Adm. Thomas Fargo, the head of the Pacific Command, Singley said.

But Fargo was told of China's growing frustration over Taiwan and what it fears is Chen's intention to push for independence during his second four-year term, which began May 20. The Bush administration's national security adviser, Condoleezza Rice, got a similar message when she visited here this month.

Former Chinese president Jiang Zemin, who heads the Communist Party's Central Military Commission, was reported recently to have told military leaders that China should take steps to recover Taiwan by the year 2020. Tao, although uncertain of the accuracy of the remarks attributed to Jiang, said that as reported they should not be seen as a military deadline but rather as an expression of a national goal over the next two decades.

"That means we realize it will take years to solve the Taiwan issue," he said.

A fighter jet took off from a Taiwanese highway last week, the first such use of the freeways since the 1970s.Taiwan held live-fire artillery drills Saturday during annual exercises.