WASHINGTON (AP) _ Close to 1 million new semiautomatic assault-style rifles could flood the United States if the Bush administration decides to end its suspension of such imports.

Gun importers have applications to bring in 965,000 of the weapons pending at the Bureau of Alcohol, Tobacco and Firearms, according to spokesman Dick Pedersen.

The import suspension was imposed March 14 after public and police outcries over the increased use of the weapons such as semiautomatic versions of AK-47s and Uzi carbines in drug-related violence, and the January slayings of five schoolchildren in Stockton, Calif..

The suspension covered some 400,000 weapons including about 300,000 for which import permits already had been approved. Last week, the administration expanded the suspension to cover 240,000 separate weapons.

''We noticed the increase in these showing up in crimes, an increase in demand, and we reacted to it,'' Pedersen said. ''The main thing is that we might be nipping the semiautomatic assault-type rifle in the bud rather than have millions of them flooding in here.''

Nevertheless, gun importers are continuing to submit applications, he said Tuesday.

''It appears there have been a lot more applications that came in after the ban,'' Pedersen said.

The Bureau of Alcohol, Tobacco and Firearms is required by law to permit imports only of weapons suitable or adaptable to ''sporting purposes,'' and it is studying the use of the semiautomatic rifles to determine how they are being used. The review should take two to three months more months.

Despite the uproar over such weapons, FBI crime statistics reveal that most murders by firearms are still committed by people wielding handguns. Of the 17,859 murders committed nationwide in 1987, 10,556 were committed with firearms of which 7,807 were handguns, according to the FBI.

Drug Enforcement Administration spokesman Con Dougherty says that increasing numbers of powerful and sophisticated handguns such as the 9mm semiautomatic, particularly guns such as the Uzi pistol, are being confiscated during arrests.

Nevertheless, Pedersen said it is extremely unlikely that the current import suspension on rifles will be expanded to any handguns.

''Handguns are used in sport, in target shooting, extensively,'' Pedersen said. ''That's negligible as far as assault weapons are concerned.''

Many local and federal police agencies have recently begun to arm themselves with foreign-made 9mm semiautomatic handguns, he said.

It would be up to Congress to make any changes in the availability of such guns, he said.

Sen. Howard Metzenbaum, D-Ohio, has introduced a bill that would place some of the same restrictions on both semiautomatic machine-style pistols and assault-style rifles that are now imposed on automatic weapons, including FBI background checks on purchasers and fingerprinting, but not the $200 fee charged to owners of machine guns, according to the senator's spokeswoman, Nancy Coffey.

Among the semiautomatic handguns that would be restricted if Metzenbaum's bill passes are the Uzi pistol, the Ingram Mac 10 and Mac 11 and the Tec 9 and Tec 22, she said.

About 231,000 foreign handguns, including semiautomatic weapons, were imported in 1986, the last year for which Pedersen had data. There was no breakdown for the number of semiautomatic handguns, he said.

The number of hanguns being imported has ''been decreasing over the years,'' while more than 1 million handguns have been produced domestically each year, he said.

In 1982, some 332,000 handguns were imported, followed by 411,000 in 1983, 341,000 in 1984 and 229,000 in 1985.

Greg Risch of Handgun Control Inc. said police are finding assault-style handguns that ''have clips that hold 30, 40, sometimes 50 rounds of ammunition, but yet are still fairly concealable, as opposed to an assault rifle that is more concealable than a hunting rifle, but still a large size.''