An increasing number of highly sophisticated and dangerous firearms are showing up on the streets of Washington, prompting D.C. police officials to consider equipping patrol officers with more advanced weapons that can be fired and reloaded more rapidly.

Rank-and-file police officers here have joined thousands of officers across the country in pressuring their departments to issue them semiautomatic pistols similar to those in the hands of drug dealers and other criminals.

In the last several weeks, District patrol officers have confiscated a growing number of semiautomatic and automatic weapons, including an Uzi-style submachine gun and an Uzi carbine, according to a police department circular distributed this month by Police Chief Maurice T. Turner Jr. to every officer.

"It's a new phenomenon," said Gary Hankins, chairman of the labor committee of the Fraternal Order of Police. "Until last year, automatic weapons were virtually nonexistent on the streets of Washington. It's become increasingly clear that the average criminal that we deal with now has outgunned the police."

Capt. William White III, a police spokesman, said that in the last six months, seven automatic or semiautomatic weapons that resemble submachine guns have been confiscated by police, compared with six such weapons seized in the previous 12 months. One such weapon was seized in 1985 and two in 1984.

"These weapons have the capability of firing anywhere from 20 to 32 times without having to reload the gun," White said.

A semiautomatic weapon fires each time the trigger is squeezed. "In a fully automatic weapon, as long as you depress the trigger the weapon will fire. Many of them will fire hundreds of rounds a minute," Hankins said.

Many officers want the department to issue 9 mm semiautomatic pistols to replace the 4-inch-barrel Smith & Wesson and Colt .38-caliber revolvers that D.C. officers carry, Hankins said. The major differences are that a semiautomatic pistol can fire 16 rounds and a revolver holds six rounds, and revolvers require a stronger trigger pull, police said.

"So if you're involved in an exchange of gunfire, you're going to run out of ammunition long before your opponent does and while you're trying to reload, you're exposed to deadly fire without defense," said Hankins.

A growing number of police departments nationwide are permitting their officers to carry semiautomatic weapons, according to law enforcement officials.

The Los Angeles Police Department allows its officers to carry semiautomatic pistols under a two-year pilot program. Houston police officers buy their own weapons, and after one year of experience on the force they are permitted to carry semiautomatic pistols. Since 1970, Chicago patrol officers have been permitted to carry semiautomatics along with their revolvers. Chicago officers, who also buy their own weapons, have to qualify to carry semiautomatics and are retested on the firing range each year.

The Largo, Fla., police department is converting to the 9 mm semiautomatic, said Holley Stever, one of Largo's 106 officers. "An officer was killed in Bay Palms last month trying to reload his revolver that had only six rounds. The semiautomatic is also much easier to load in the dark when your hand is shaking with adrenalin."

The D.C. police department already issues semiautomatic pistols to members of its Emergency Response Team, which responds to such situations as barricades and terrorist acts. The department has not issued the pistols to every officer, partly because of the increased cost and the belief of some officials that the revolver now in use is adequate.

White said that the semiautomatic weapons also come with a higher possibility of accidentally discharging or jamming.

But the police spokesman said the department is concerned that officers may be at a disadvantage when they confront a criminal armed with an automatic weapon.

"The department is conducting a study and survey involving other urban police departments throughout the country to determine whether or not the handguns we currently issue are adequate in light of the recent increase in drug-related violence," White said. "Fifty-three percent of the homicides committed have been drug-related, which reflects an increase in the type of violent crimes that are occurring within the city.

"Under no circumstance do we want to put members of the department in a life-threatening situation because of inadequate equipment."

Police officials said that because of escalating violence and the increasing use of automatic weapons on D.C. streets, a number of agents with the federal Bureau of Alcohol, Tobacco and Firearms will begin to help police trace the origin of those weapons.

"The difference between an automatic weapon and a service revolver is devastating," said Hankins. "If you have an automatic weapon, you can point the gun in the direction of the officer and shoot 15 or 20 rounds and you have 15 or 20 chances of hitting that officer in one second or two seconds, while he can get off maybe one round in that same period of time and his chances of hitting you are once."

Police officials said that a conversion to new police weapons would be costly because more than 3,000 new pistols would have to be purchased. But patrol officers argue that the cost would be reduced by a trade-in of their revolvers. "With a trade-in, the new weapons would cost a couple of hundred dollars each," Hankins said. "The cost of switching would be less than 1 percent of the budget, and given the threat that we're facing, I don't think that's expensive at all."

In a similar push to protect themselves five years ago, the police union demanded that the department equip its members with bullet-proof vests. The department issued the vests after money was raised from the city and private donations.