The Army says it may be able to field a new generation of defenses against short-range missiles such as the Iraqi Scud by the mid-1990s, but it is unclear whether such a system would comply with all arms treaties.

The Army's Strategic Defense Command is speeding its development of a new, more sophisticated family of anti-missile missiles that would represent a gigantic technological leap beyond the Patriot system that now is the nation's only means of shooting down short-range ballistic missiles.The Patriot, which gained fame for intercepting Scuds over Israel and Saudi Arabia during the Persian Gulf war, would revert to its original role of defending mainly against aircraft rather than ballistic missiles, officials said.

Lt. Gen. Robert Hammond, commander of the Strategic Defense Command based here, said Tuesday that a new-generation defense against short-range missiles could be ready for use by about 1995. Congress has shown much greater interest in financing such a system in the aftermath of the gulf war, although it remains reluctant to increase spending on defenses against strategic, or intercontinental, missiles.

Hammond said there was doubt, however, whether the system envisioned by the Army would comply fully with the 1972 Anti-Ballistic Missile Treaty that outlaws large-scale defenses against strategic missiles.

He said a key question was whether the intended range of the new U.S. missiles - reaching about 100 miles into the atmosphere - would require the U.S. government to seek a modification of the ABM treaty before performing some tests.

"There is a question at this time on whether we can do everything we want to do" in the anti-missile program without persuading the Soviet Union to modify the treaty, Hammond told reporters. But he added: "It's not causing us too much gray hair."

If the new anti-missile missiles perform as designed, they would virtually eliminate the problem of debris from exploded missiles falling to earth and inflicting potentially heavy damage on populated areas, Army officials said.

During the gulf war, the Patriots that intercepted Scuds did not destroy the missiles. Scud debris - and in some cases the warhead - crashed to the ground in Israel and Saudi Arabia, causing extensive damage.

A new missile now in development, called the Erint, would travel at such high speed and hit an incoming missile with such accuracy that it would literally vaporize the target - including any warhead, whether conventional or nuclear, said Joseph Butler, the Erint program manager.

The Patriot is not capable of such complete destruction because it attacks its target by detonating its own warhead just as it approaches the target. This causes metal fragments from the Patriot warhead to "kill" the incoming missile, but it does not stop parts of the target from continuing to fall to earth.