DUNCANVILLE, Texas (AP) _ An off-duty Dallas police sergeant was shot dead by police in this suburb early Sunday as he brandished a gun and tried to enter his home after an argument with his wife, authorities said.

Police Sgt. Glenn Repp III repeatedly ordered Dallas Sgt. Larry Wise to ''Drop it, Larry'' before both men opened fire at a range of about 20 feet, said Duncanville police spokesman Dan Robertson.

Wise, hit once in the chest, died about 50 minutes later at 4:05 a.m. at Charlton Methodist Hospital, Robertson said.

Repp and his partner, Officer Stacy Holden, were not wounded.

Wise, a 20-year police veteran, lived at the house with his wife, Cindy, police said. The couple, who had once been separated, had gotten into an argument at a nightclub earlier in the evening while celebrating Mrs. Wise's birthday.

Wise's sister-in-law, Brenda Smith, told police he made threats, Robertson said.

Ms. Smith, fearing for the safety of Wise's 13-year-old son and a teen-age friend, went to pick up the youngsters, and asked police to accompany her.

Repp and Holden arrived at Wise's home just before he did, Robertson said. Wise spotted the officers and pointed his gun at them, then lowered it and headed for the door.

The officers, who sought cover behind their car when Wise raised his weapon, were approaching him when the shooting broke out.

Robertson said police weren't sure who fired the first shot, but Dallas police spokesman Hollis Edwards said Duncanville police told him Wise fired first and Repp returned fire in self-defense.

Ms. Smith and a male friend pulled up in time to see the shooting, Robertson said.

Mrs. Wise arrived afterwards, and took the teen-agers to a neighbor's home, friends said.

Carl Chapman, who lives across the street from the Wise home, said Wise ''was a nice guy.'' Other neighbors, who asked not to be identified, said they had never seen trouble between the couple.

Repp, who knew Wise professionally, was put on a one-week leave.

Robertson said the Duncanville and Dallas departments work together daily, and said he hoped the shooting wouldn't change the relationship between the two forces.

''We hope the (Dallas) officers can see our officers only did what they had to do,'' he said.