WASHINGTON — Greyhound offered $100,000 rewards Tuesday for information about bus shootings in the nearly monthlong driver’s strike, a move the union called a ploy to keep negotiations stalled.

“They’re using that as a smoke screen to avoid coming back to the bargaining table,” Edward M. Strait, president of the Amalgamated Council of Greyhound Local Unions, said as he and a handful of other union members picketed outside the building where the rewards were announced.

P. Anthony Lannie, vice president and chief negotiator for Greyhound Lines Inc., said $100,000 would be paid for information leading to convictions for shooting at buses and terminals.

Since the strike started March 2, there have been attacks on 21 Greyhound buses and two attacks on terminals, Lannie said. The latest violence occurred Monday night, when a shotgun was fired into a terminal in Amarillo, Texas, and a bus was hit with gunfire near Orlando, Fla., he said.

Numerous other buses have been pelted with bricks and rocks, the company said. Several bomb threats also have been placed, officials said.

“The terrorism must stop,” Lannie said. “It’s inevitable that somebody is going to be hurt.”

No one has been seriously injured in any of the shootings on buses or terminals. But on the second day of the walkout, a striking driver in Redding, Calif., was crushed to death by a bus driven by a replacement driver. No one was charged.

“We don’t condone violence. Never have,” Strait said, adding that there have been at least 60 incidents in which pickets have been injured.

Union members have been told the union will back prosecution for strike-related violence, Strait said.

Also Tuesday, the West Hartford, Conn., case against a striking driver accused of shooting at a bus two weeks ago was moved to Hartford Superior Court so officials there can determine whether more serious charges are warranted.