Store owners in the Washington-Baltimore area are hiring shotgun-armed guards and pooling hundreds of thousand of dollars in reward money in an effort to halt what they call as unprecedented wave of thefts by a gang of "smash-and-grab" burglars.

Department store security officials said the thieves have struck more than 80 stores in the Washington area in the last six months and have made off with about $1 million worth of jewelry, furs and other merchandise.

In the most recent case, Garfinckel's department store in downtown Washington was struck Thursday night by burglars using a method now familiar to police and store officials. The thieves smashed a door on the F Street side of the building, broke into the display cases in the fine jewelry department and escaped before police arrived in response to the burglar alarm.

Woodward & Lothrop, which has lost more than $250,000 in merchandise in two recent burglaries, has posted armed guards on the floors of some stores at night with orders to fire on thieves, the stores' security chief said yesterday.

"We hope they smash into one of our stores at night now, because they'll be in for a big surprise," said Louis Shealy. "Somebody will get killed. We're going to do whatever we have to to stop these people because we've really been taking a beating.

"This is clearly an organized effort by criminals," Shealy said. "The stores are cased out in advance, and everything is timed and planned. These are professional jobs."

Shealy said that local police, who have coordinated their investigations of the burglaries, have identified more than 20 suspects.

Although all of the suspects are local residents, Shealy and other officials said similar smash-and-grab burglaries have been staged in Atlanta, Los Angeles, and New York.

The thieves use a simple, violent technique to circumvent the elaborate security systems of jewelry and department stores, police said. A window or door is broken with a brick, and the burglars run into the store and carry out valuables before police arrive.

In addition to identifying the merchandise they intend to steal in advance, the thieves sometimes smash a window and clock the time it takes for police to arrive, officials said. When the actual thefts are carried out the thieves rarely spend more than five minutes in a store.

One of the most spectacular of the crimes occurred on Nov. 2, when burglars broke a window at the Annapolis Woodward & Lorthrop store and made off with more than $200,000 in gold jewelry. State police investigating that case said yesterday they still had no leads or suspects.

Woodies published newspaper advertisements yesterday offering a $10,000 reward for information leading to arrests or recovery of merchandise from the Annapolis burglary.

Shealy said yesterday that Woodward & Lothrop plans to join several other major department stores, including Hechts and Garfinckel's, to announce a larger reward offer.

"We want to have a combined reward of one or two hundred thousand dollars," Shealy said. "It's the only way to stop something that's this big."

The chief of the District of Columbia police burglary squad, Capt. Jimmy Wilson, said yesterday his entire command of more than 20 officers is working on the smash-and-grab thefts and that a liaison officer had been appointed to help coordinate activities with other departments.

Wilson said District police have arranged a meeting of area jewelry and department store owners next week to discuss the wave of burglaries. Store owners will be briefed on the burglars' technique and on additional security measures they could take. Those measures include installation of unbreakable plexiglas windows.

Although police are not sure if the smash-and-grab burglars belong to one or more gangs, the wave of crime appears to have moved in patterns around the area.

Montgomery County police said yesterday 10 of the crimes were committed in the county between June and October, but there have been none since then. Police say there has been an increase in the number of stores struck in the District, Prince George's County and Baltimore in recent weeks.

Shealy and other local security officials suggested yesterday that the recent arrest of four people in Anacostia Park accused of trading in stolen jewelry represented progress in the case.

But Wilson said yesterday District police are still investigating and would not comment on a possible relationship between the arrests and the smash-and-grab crimes.