Madrid, Spain (CNN) -- Spain on Sunday marks the eighth anniversary of the Madrid train bombings, this year embroiled in controversy over a decision by unions to hold nationwide protests over the economic crisis.
Some of the usual anniversary observances will be held on Sunday to remember the 191 people killed and more than 1,800 wounded in the terrorist attacks on morning rush-hour commuter trains on March 11, 2004.
But other observances, usually held on the day of the anniversary, will this year be pushed back a day, until Monday, due to the union protest.
Spain's anniversary observances in recent years have been subdued, without the King or prime minister attending, and without speeches or music. Authorities have said that's in keeping with the wishes of the victims associations, who want the nation to remember but without undue fanfare.
The ceremonies include placing of floral wreaths and long moments of silence.
But for the first time, Spain's two main unions have scheduled dozens of protests nationwide on the anniversary and that has prompted criticism from some conservative leaders who accuse the unions of disrespect for the victims.
The unions have countered that some conservatives have repeatedly shown a lack of respect for the victims -- which included many workers and students killed or maimed in the attacks -- by fomenting unfounded conspiracy theories about the bombings.
Spain's two main unions -- the Socialist-leaning General Workers Union (UGT) and the Communist-leaning Workers Commissions (CCOO) -- scheduled the demonstrations on March 11 to protest against the new conservative government's labor reforms, which unions say make it cheaper and easier to fire workers.
The March 11 demonstrations follow union protests last month which drew large crowds nationwide. On Friday, the unions announced a general strike for March 29.
Spain's jobless rate is nearly 23 percent overall, and nearly 50 percent for youth. Nearly 5.3 million Spaniards are out of work and the government has announced deep austerity cuts.
The unions said the protest in Madrid will take a different route on March 11 than the protests last month, out of respect for the victims. The route on Sunday will avoid the Atocha train station, which took the brunt of the casualties, and the emblematic Puerta del Sol square in the city center.
The UGT union has announced that Pilar Manjon, a leader of the largest victims association whose son died in the attacks, will join union members at the Atocha station on Sunday morning for a memorial observance, before the protest march.
Nearby, in the Retiro Park, at a grove of trees planted in honor of the victims, the Association of Victims of Terrorism will hold a memorial.
But Madrid's regional government and Madrid's city hall, both governed by conservative administrations, have decided to delay until Monday their annual observances. They will include a memorial ceremony in the Puerta del Sol, followed by a memorial in the monument to the victims at Atocha station.
Spanish courts already have convicted 14 Islamic militants for their roles in the train bombings, along with four Spaniards convicted for trafficking in explosives used in the attacks.
Additionally, seven other prime Islamic suspects in the attacks blew themselves up three weeks after the train bombings as police closed in on their hideout in a Madrid suburb. That explosion also killed a police officer and wounded various others.