NEW YORK, JUNE 30 -- A grenade with wires attached was found outside Lincoln Center today and delayed the start of a performance by the Soviet Bolshoi Ballet company, but police said the device contained no explosives and labeled it "a hoax."

"It was a Mark II military grenade shell with four batteries and clock inside," police spokesman Sgt. John Venetucci said.

The curtain went up at 8:22 p.m. -- almost an hour late -- after opera house security officers with metal detectors searched long lines of ticket holders anticipating the Bolshoi's first New York apprearance in eight years.

The device was discovered at 3:45 p.m. in a trash can on Lincoln Center plaza, police said. They evacuated the plaza and trained dogs sniffed the opera house for explosives. It was not until 8:35 p.m. that the device was determined to be harmless.

Minutes before it was found, an unidentified caller telephoned United Press International and said, "Bomb. Lincoln Square Plaza. Death to Soviet dancers."

Across from the opera house, some 60 pickets demonstrating against Soviet treatment of Jews protested the performance, but denied responsibility for planting the hoax grenade.

In September, about 20 people were injured when a tear gas canister was rolled into the Metropolitan Opera House during the opening performance of the Soviet Moysiev Folk Dance Company.

Met spokesman Johanna Fiedler said opera house security had been strengthened for the Bolshoi's 21 performances but would not give details.