President Clinton has ordered a second Navy aircraft carrier group to join one already in the waters near Taiwan as tensions mount between China and Taiwan, sources said.

The dispatch of the second carrier group comes as Secretary of State Warren Christopher warned China yesterday that the military exercises it is holding in the Taiwan Strait are "unnecessarily risky" and "unnecessarily reckless" and that belligerent actions against Taiwan would have "grave consequences."

Pentagon officials said yesterday that the carrier USS Independence and three warships were ordered Saturday to move to within about 100 miles of the Taiwan Strait.

Administration officials said the Pentagon will announce today that the nuclear-powered carrier USS Nimitz and five or six accompanying ships will arrive from the Persian Gulf a few days before Taiwan's March 23 presidential election.

Christopher declined to say what the battle groups would do. "We're concerned to make sure those forces . . . are in a position to be helpful if they need to be," he said on NBC's "Meet the Press."

On Friday China began testing guided missiles within 30 miles of Taiwan. China ratcheted up the regional tensions Saturday when it announced that it would hold live-ammunition war games in the strait that will run until March 20.

National security adviser Anthony Lake, in an appearance yesterday on ABC's "This Week With David Brinkley," said that "if there are accidents" in the military exercises, China "will be held accountable. And we have also said that if they attack Taiwan, there will be grave consequences."

Several U.S. officials said that the administration has no reason to doubt Beijing's public assurances that it does not intend to use the military exercises as a cover for invading Taiwan, a self-governing island that China considers to be a province of China. "We have no evidence" to suggest the exercises will lead to conflict, one official said, "but we want to be prudent."

Another official described the decision to move the carrier task forces as an effort to deter any Chinese adventurism. The U.S. ships and planes will "monitor the activities" of Chinese forces and "ensure that the stated purpose {of the military exercise} remains the actual purpose."

U.S. officials have no plans at present to sail the U.S. vessels through the Taiwan Strait, seeing no need to conduct such a maneuver at this time, several officials said. The Nimitz and four escort vessels sailed through the strait in December in a maneuver that U.S. officials described as sending a message to Beijing to refrain from military action against Taiwan.

The movement of U.S. naval forces was announced after U.S. officials held a lengthy meeting on Friday with a top Chinese official, Liu Huaqui, who reiterated Beijing's claim that China's relationship with Taiwan was an internal matter, according to an administration official familiar with the talks.

Liu saved his harshest criticism for the Taiwanese government, which he said had provoked the current dispute. But he also accused Washington of interfering wrongfully. "He was basically trying to convince us to stand aside while they intimidate Taiwan, and that's not happening," a senior official said.

The unusual meeting between Liu, who is the foreign affairs director of China's State Council and a rough counterpart to Lake, and various U.S. officials covered a wide range of topics in U.S.-China relations, reflecting what one official described as an effort to "talk through the nature of our relationship, get an understanding of mutual strategic interests and how we each assert our interests and defend them in ways that do not blow up our relationship."

In addition to reiterating U.S. complaints that the Chinese missile firings and military exercises are reckless, Lake and other U.S. officials tried to convince Liu that Beijing's campaign of intimidation would backfire by shoring up support in Taiwan for the country's pro-democracy candidate Lee Teng-Hui in the first democratic elections in the island's history.

Beijing has complained that Lee is pursuing a separatist policy contrary to past pledges of eventual reunification between Taiwan and its 21 million inhabitants and the Chinese mainland.

The meeting between Liu and U.S. officials, which was held at U.S. Ambassador to France Pamela Harriman's Virginia farm, produced few concrete gains on other contentious issues such as alleged Chinese arms proliferation, copying of U.S. trademark goods, or violations of human rights, according to U.S. officials. One called the discussion of China's cooperation with Pakistan's nuclear weapons program and Iran's chemical arms program "interesting but not satisfactory." Lake said in an interview that the dispatch of the carrier groups represented "prudent steps. Any time there is a crisis in an area where our interests are . . . we move our ships in."

One administration official aware of the planning described the convoy as the "largest U.S. force in the region in the recent past."

Once assembled, the Navy force will include 110 to 130 carrier-based strike aircraft and ships with well over 200 Tomahawk cruise missiles on board. In addition, the battle groups will be accompanied by submarines that bring special, hard-to-detect weaponry and surveillance capabilities. Staff writer R. Jeffrey Smith contributed to this report.