In Washington, Michael D. McCurry, the White House spokesman, and other Administration officials seemed to take pains to avoid criticizing Beijing for ordering the expulsions. Mr. McCurry said he doubted there would be "negative repercussions" from the incident.

The Pentagon official was more cautious, saying: "We're trying to be non-inflammatory about this until they are safe. We won't know for sure until they're out."

Richard Baum, professor of political science at the University of California at Los Angeles, said today that the recent worsening of tension between China and Taiwan undoubtedly put a premium on information about how China is mobilizing its forces in the southeast, across the straits from Taiwan.

China is conducting a broad three-month military exercise in its southeast region, and only 12 days ago launched four test missiles aimed at a target 80 miles north of Taiwan.

"With the missile tests, the threat of reaction if Taiwan pursues the nuclear option, it's not surprising that there is increased interest in what is going on in places like Fujian and Guangdong," said Mr. Baum. Last week Taiwan's President, Lee Teng-hui, said Taiwan might consider the possibility of developing nuclear weapons.

The two officers were carrying their personal cameras, which is normal for defense liaison officers, the Pentagon officials said, and they may have been taking pictures of exercises when they were detained.

It was not immediately clear why China publicly announced apprehending American military officers, rather than expelling them quietly. Nor was it clear whether the decision to announce the incident reflected irritation among some Chinese leaders at the presence of American military officers in China.