The Montgomery County Police Department is putting into effect today a new general order which narrows the circumstances under which officers may use their firearms.

In an attempt to avoid the kind of situation which occurred recently in Prince George's county, where a county police officer shot and killed an unarmed shoplifting suspect last Christmas Eve, the Montgomery department's new policy restricts the officer's authority to use his gun when trying to apprehend a fleeing felon.

From now on an officer may shoot at fleeing suspects only if "the officer has probable cause to believe a violent crime has just occurred." Violent crime is described in the general order as murder, assault with intent to murder, rape, first degree sexual assault and armed robbery.

The new general order leaves unchanged the policy that permits officers to use deadly force to defend themselves or other persons when they are threatened with death or serious injury.

The problem with the old policy, according to Police Chief Robert J. Di-Grazia, is that it gave police officers the right to shoot at any fleeing felons.

"A fleeing felon could mean a 14-year-old on a "stolen" $100 Schwinn bicycle . . . under the previous policy that would entitle him to be shot. That's no longer the case," added Pfc. Robert Croskery, who coordinated the chief's efforts to revise the firearms regulations.

Before shooting at a suspect, an officer now must have witnessed the crime or have "credible evidence" that the suspect is the person responsible for the crime.

Under the new order, officers are forbidden to remove their shotguns from their police cars even if a felony is in progress if there are innocent bystanders in the vicinity.

The new policy also prohibits officers from firing warning shots into the ground as a means of calling for assistance from fellow officers. The firing of warning shots to force suspects to halt was banned a few years ago.

Additionally, the new order permits, but discourages, firing shots from or at a moving vehicle.

Earlier this year, the Prince George's County police, adopted a firearms policy which requires officers to "have more than a suspicion" of a clear and present danger before firing their weapons. Warning shots were also banned at that time.

DiGrzia said the Montgomery order was not put into effect because there is a problem wih police use of firearms in Montgomery. He also denied that the new order was issued because of publicity the Prince George's county department received in recent months over the controversial shooting deaths of two black suspects by white officers.

In 1977 a suspect and an innocent bystander were shot by a Montgomery County police officer during a robbery at a High's store. Last February a cab driver, who had been kidnapped, was critically wounded by police who shot at a suspect who was seated in the back of the cab.

Pfc Lenny Simpson, president of the Montgomery County Fraternal Order of Police called the new policy "a vast improvement" over the previous general order, which he called "to ambiguous and too lengthy."

"I think most of the officers are going to gladly accept the new general order," Simpson said.