Police broke up a fuel depot blockade in France on Wednesday and France's hardline CGT union prepared for a strike at a nuclear plant, escalating a standoff over proposed new labour laws.
France has also mobilised its emergency motor fuel stocks for the first time since 2010, a spokeswoman for oil lobby group UFIP said.
Ministers went on radio morning shows to say the government would stand firm, while CGT chief Philippe Martinez told RTL radio that his union, one of the most powerful in France, would press on with its strikes.
At stake is a labour reform that the government says is crucial to fight rampant unemployment stuck at over 10 percent of the workforce and which aim to make hiring and firing easier. The CGT says the reforms will unravel protective labour regulation, even though other unions back it.
So far the strikes have affected oil depot and refineries, triggering shortages, and train and metro strikes have been announced too.
The nuclear plant strike is a further escalation of a conflict that also threatens to affect the Euro 2016 football championship, which starts on June 10 in France.
The government has accused the CGT of taking the country hostage.
"A small minority is trying to radicalise things," Junior minister Jean-Marie Le Guen told RTL radio. "We will unblock the situation," he said, adding that a union "cannot govern the country."
Police used water cannons in the early hours of Wednesday to dislodge some 80 unionists who were blocking a fuel depot at Douchy-les-Mines, in northern France, union and police officials said. Other depots were unblocked by police on Tuesday.
Undeterred, CGT chief Philippe Martinez told France Inter: "We will carry on."
CGT workers have voted for a 24-hour strike starting at 1900 GMT on Wednesday at the Nogent-sur-Seine nuclear plant southeast of Paris and workers at other nuclear plants will meet today to decide on possible further strikes, Laurent Langlard, a spokesman for the CGT's energy federation said.
The union, which he said represents close to half of workers in the sector, voted for a complete halt of production at the Nogent-sur-Seine plant, he said.
UFIP spokeswoman Catherine Enck said "a small quantity" of the government's emergency stock had been drawn.