Police in Montgomery and Prince George's counties shot and killed two men in unrelated incidents during a 24-hour period, authorities said yesterday.

In Aspen Hill yesterday afternoon, Montgomery County police shot and killed a robbery suspect during a foot chase.

Four plainclothes detectives were following up on a report of suspicious activity earlier in the day at a strip shopping mall, in the 13600 block of Georgia Avenue, when they saw two men robbing someone about 4 p.m., said Julia Gilroy, a Montgomery police spokeswoman.

The detectives ran after the men. As patrol units converged on the scene, the men split up and ran into a wooded area in the 3400 block of Hewitt Avenue, off Georgia Avenue, where an officer shot one of them. Last night, police were still trying to determine the events that immediately preceded the shooting, Gilroy said. She did not know how many shots were fired.

The man, whose identity was not released, died a short time later at a hospital, Gilroy said. The second suspect was arrested.

Police found weapons in the area where the man was shot, Gilroy said, but she added that it had not been determined whether they belonged to the suspects. As is routine, the detective involved in the shooting was placed on administrative leave, Gilroy said.

On Wednesday night in Prince George's, Fairmount Heights police shot and killed a 29-year-old man whose car was parked outside the police station at 6100 Jost St., near the District border. The man was identified last night by Prince George's police as Calvin Braxton of the District.

The incident began about 6:40 p.m., when someone entered the station to report an armed man parked outside, according to the county police department, which is investigating the shooting.

Two officers approached and ordered the driver out of the car, said Cpl. Joe Merkel, a police spokesman. The man put the car in reverse and dragged an officer who might have been holding on to the car, he said.

Both officers opened fire, shooting the driver numerous times. The car stopped about 50 yards down the street. The driver was taken to Prince George's Hospital Center, where he was pronounced dead at 11:40 p.m., Merkel said.

Braxton's body was taken to the state medical examiner's office in Baltimore for an autopsy.

The officer who was dragged, whose name had not been released last night, was treated at a hospital for injuries to his hands.

Merkel declined to identify the officers involved in the shooting and referred calls to the Fairmount Heights Police Department. He said that department will determine whether the officers will face administrative action. A message left at the Fairmount Heights station was not returned last night.

Staff writer Jamie Stockwell contributed to this report.

Police cordon off part of Hewitt Avenue in Wheaton, where two robbery suspects tried to hide in woods. One was killed; the other is in custody.