Labor leaders hoped Thursday's walkout would be a show of unity unseen since strikes in 1995, during Jacques Chirac's presidency, that paralyzed the country and sapped Chirac's appetite for reform.

Transit workers initiated the strikes but employees of state-run electricity, gas and other services also could take part in the action, which was to begin Wednesday at 8 p.m. (1800 GMT) and continue through Thursday.

After months in the shadow of the powerful and popular president, unions were mounting the strikes as a cry of anger and an alert to the government as it seeks to reinvigorate the economy through changes to labor laws.

The day of strikes is aimed at protesting plans to cut back on special retirement benefits accorded to employees in state-run businesses, such as transport companies. Sarkozy, who pledged changes to France's labor protections during his election campaign this spring, deems the benefits too costly, outdated and unfair.

"I think this strike will be strong ... and I even have the feeling that there may be virtually no trains, buses or Metros," Labor Minister Xavier Bertrand said during a weekend media forum.

Still, he added, he remains "totally determined" to see through the changes — "in a spirit of dialogue."

Most unions at the national SNCF train authority and Paris' RATP transport authority were taking part in the strikes.

High-speed TGV trains — including the Eurostar route between Paris and London — will also be affected. The Eurostar will run eight trains in 10, the SNCF said in a statement Tuesday, warning that nationwide traffic would be "nearly paralyzed."

The RATP warned of "very serious disturbances" on Thursday of Metros, buses, suburban trains and tramways.

Repercussions from the transport tangle were expected to be felt in a wide swath of the French economy.

Most teachers were not planning to strike, but some schools were expected to close for fear that staff would not be able to get to class.

Air transport also faced potential disturbances, according to civil aviation authorities, who said there was a risk that flights would be "modified," particularly early in the day.

Aviation administrative employees and airport personnel could have trouble getting to work due to the transport strikes, the civil aviation authority said.

Sarkozy is looking to trim special retirement packages for chosen groups of workers — more than half a million workers plus 1.1 million current retirees.

Train and bus workers, for instance, can retire with a state pension at the age of 50. Such special privileges date from World War II and earlier, when some sectors were considered dangerous or vital to France's interests.

The strikes could overflow into Friday. Three train federations were calling for a daily vote to see whether to extend the strikes.

It was not the only front in Sarkozy's reform battle.

Hospital interns and doctors completing residencies have been striking overnight and on-call duties since Sept. 27 to protest plans to outlaw new medical offices in large cities in favor of regions where doctors are less numerous.