Three people were slain and three others were wounded in shootings in the city this weekend, including one in which a man who tried to rob a pizza store was critically injured when its owner fought back, police said yesterday.

The attempted robbery occurred at 11:43 p.m. Saturday at Tony's Place, a pizzeria on Frankford Avenue near Cambria Street, in Kensington.

A masked gunman in his mid-20s burst into the restaurant, demanding money, police spokeswoman Officer Christine O'Brien said.

The 43-year-old store owner pushed away the would-be robber's gun, and then a friend of the owner who was inside the shop tried to wrestle the gun away from the man, police said.

During the struggle, the robber fired two shots, but no one was injured, O'Brien said.

The owner, who had a permit to carry a concealed weapon, then pulled out his own firearm and shot the man in the back and shoulder, police said.

The gunman, who was not identified by police, was taken to Temple University Hospital, where he was in critical condition and being held as a prisoner.

He was expected to be charged with robbery and related offenses once he regains consciousness, police said.

The owner and his friend were not identified by police but neither is expected to face charges. Calls to the pizzeria were not answered yesterday.

* Last night, a man and woman were hospitalized after being shot about 9:30 p.m. in North Philadelphia, police said.

The shooting occurred at 24th and Berks streets, Central Detectives said. Both victims were taken to Temple University Hospital, where the man was in critical condition with at least one chest wound and the woman was in stable condition, police said.

* About 5 a.m. yesterday, police received a call about a person with a gun at a house on 7th Street near Indiana Avenue in North Philadelphia.

Upon arrival, police found Frederick Johnson, 38, lying face- down with a gunshot wound to the head in the living room of the house. Medics pronounced John-son, of 10th Street near Erie Avenue in North Philadelphia, dead upon arrival.

According to police, a gunman entered the house where Johnson had been and shot him once before fleeing.

* On Saturday, John Hightower, 24, of Griscom Street near Adams Avenue, was walking with three friends about 11 p.m. on Redfield Street near Master in West Philadelphia when he and his group were approached by two men, one of whom was carrying a sawed-off shotgun, police said.

The two men demanded money from Hightower and his friends and came away with $85, a cell phone and a pack of cigarettes, police said.

The man with the shotgun fired once at Hightower's face, but left his friends alone, police said. Hightower was pronounced dead at the scene at 11:10 p.m., police said.

* About 11:35 p.m. Friday, police responding to reports of a person with a gun inside Cousin Danny's Exotic Dance Haven, on 52nd Street near Spruce, found a man with three gunshot wounds in his back. Orlando Morrison, 27, of Webster Street near 58th in West Philadelphia, was pronounced dead at 11:45 p.m. the Hospital of the University of Pennsylvania, police said.

There were no arrests.