Pakistani scientists and weapons experts are studying components salvaged from an errant American cruise missile that landed last week in southern Pakistan, security sources said today. They expressed optimism that they could unlock technological secrets that will advance Pakistan's missile program.

Officials said experts associated with Pakistan's civilian and military missile programs were inspecting the guidance system, onboard computer and propulsion system of the Tomahawk missile, which was fired Aug. 20 in the U.S. attack on Islamic terrorist camps in Afghanistan but apparently fell short of its target.

Some sources indicated that information obtained by examining the missile might be shared with China, Pakistan's ally, but officials here refused to comment on that possibility.

A Pakistani official speaking on condition of anonymity said the find was "a jackpot" that included the satellite global positioning system and other technological improvements made to Tomahawks since the 1991 Persian Gulf War. "We have missile experts who would most certainly demonstrate a remarkable job of reverse engineering" and develop technological know-how that Pakistan lacks, the official said.

Pakistan reported earlier this week that it had recovered the missile Saturday near Kharan, about 370 miles south of the targeted camps in Afghanistan. Pentagon officials have declined to confirm that a missile landed in Pakistan or to comment on the implications for Pakistan and China, which hope to acquire cruise missiles. The Pakistani sources noted with some surprise that the missile was largely intact when it was discovered. Sources in Washington said the Tomahawk might not have detonated because the arming mechanism is not activated until minutes before the missile reaches its target. But retired Lt. Gen. Thomas G. McInerney said he doubts the Pakistani claims. When cruise missiles crash, he said, "its like dropping a Waterford crystal glass. They are designed to do a lot of things, but they aren't designed to bounce. They are very fragile." What did not break apart on impact would probably have been burned by the missile's fuel, which would ignite on impact, he said.

U.S. defense officials also scoffed at the notion that the Pakistanis had gained an intelligence windfall, suggesting that the Tomahawk's technology already is widely available and noting that the loss of several such missiles during the Persian Gulf War is not known to have produced any breakthroughs for Iraq.

But a ranking security official in Islamabad, the Pakistani capital, pointed out that restrictions on technological transfers between the United States and Pakistan have been in effect for nearly a decade. Since 1990, when Washington cut military aid because it believed Pakistan had developed a nuclear bomb, information that the Pentagon might readily provide to another nation would have been harder to come by here, he said.

"It is a gift from God," the official said. "The country that had denied us all sorts of economic and military assistance has suddenly gifted us the weapon of choice from its arsenal."

He voiced a note of caution, however, saying: "This will definitely enhance our knowledge about the latest missile technology, but how much it is too early to predict."

Other sources here acknowledged, though, that it is unlikely Pakistan could extract enough information from the Tomahawk components to reproduce such a missile. They said, however, that their need for the kind of advanced weaponry found in U.S. arsenals is limited and that they would be happy for even limited gains in missile technology.

"Pakistan is not {a} global player," one official said, adding that its defense needs are geared more toward dealing with "its arch-rival that lives next door."

Tensions between Pakistan and neighboring India, with which it has fought three wars in the last 51 years, have been high since both nations tested nuclear devices in May. While their nuclear programs have been the focus of world attention, the rivals' competition to develop more advanced, longer-range missiles has been almost as intense.

Officials declined to comment on whether Pakistan might share any discoveries with China, a close ally that the United States has repeatedly accused of helping Pakistan with its missile program.

Gen. Jehangir Karamat, head of Pakistan's joint chiefs of staff, is touring China, and a senior army official said today that he has been briefed on initial reports from Pakistani scientists on the Tomahawk. "In view of extremely close ties between the two military services," the official said, he would be surprised if the findings were not discussed with Chinese officials.

U.S. government and private cruise missile experts said that while an intact Tomahawk would be of limited benefit to the Pakistanis, it could be of significant help to the more advanced Chinese military. Of immediate concern, said K. Scott McMahon, a national security expert with Pacific-Sierra Research Corp., an Arlington-based defense consultant firm, would be the ability of the Chinese to incorporate the missile's radar image into the air defense systems it sells to such nations as Albania, Iran, North Korea and Pakistan. "It would enable the Chinese to enhance their air defense system against what is arguably the most serious missile threat out there," McMahon said. "The air defense implications for the Chinese are something we have to be seriously concerned about."

Experts said the Chinese have the technological know-how to study and eventually copy the missile's guidance system, which matches photographic images of a target and surrounding terrain against the actual terrain it flies over. It also incorporates a satellite-based global positioning system. They added that the Chinese also could gain useful knowledge from studying the missile's airframe material, electronics, warhead and turbo-fan engine. Staff writers Dana Priest and Bradley Graham in Washington contributed to this report. CAPTION: U.S. officials doubt Pakistan salvaged a Tomahawk missile, such as above.