One suburban Washington man was shot and killed and another seriously wounded outside the crowded Capital Centre in Landover last night shortly before a concert by the British rock group the Rolling Stones.

The shooting occurred about 7:30 p.m. on the edge of a wooded area near the center's parking lot as thousands prepared to enter the arena for the featured event, scheduled for 10. Authorities said early today they were unable to explain the shooting, which took the life of Richard L. Wright, 21, of Beltsville.

Wright, who suffered multiple gunshot wounds, was taken to Prince George's General Hospital where he died in the operating room about an hour later.

Andrew J. Ulsaker, 21, also of Beltsville, who had accompanied Wright to the concert, was listed in fair condition at the hospital, suffering from a gunshot wound in the right side of his chest.

According to police, Ulsaker and Wright had walked a short distance from the Capital Centre property to find a spot away from the crowd to relieve themselves.

A few minutes later, the wounded Ulsaker approached a policeman directing traffic, saying: "My friend's been shot . . . I've been shot too."

Authorities said Ulsaker told them he and Wright encountered two other persons near the woods and that an altercation ensued. Police were unable to give further details, and early this morning said they had yet to discover a motive for the shooting and were still searching for suspects.

According to an Ulsaker family member, the two men were roommates in an apartment on the 11300 block of Cherry Hill Road in Beltsville. Wright was employed with a construction firm, the family member said. Ulsaker works odd jobs.

Apparently few of the 18,000 people who attended the concert were ever aware of the incident. The Rolling Stones went on stage at 10:10 and played until past midnight.

A spokesman for the concert's promoters said, "The first thing anyone backstage knew about it was when the [television] news came on" at 11 o'clock.